So, here is the problem: We are building a wooden house from a bar. House on a strip foundation. There is already a roof, windows, doors, a draft floor has been made (see) with insulation and we begin to lay the final floor. In the spring, after the snow has melted, I notice that the boards lined from below to subfloor became damp and even covered with mold, fungus (despite the fact that they were treated with biosecurity).
What to do in this case, if dampness, humidity, or even mold has appeared under the floor in a wooden house?
After browsing a bunch of sites on the Internet, talking to experienced summer residents and individual developers, I have put together for myself the following set of relatively simple measures to get rid of dampness under the floor. What I want to write about now.
First, it should be noted that there are two reasons why the floor is damp:
Moisture penetration. Water passes outside through the ground, under the foundation strip and rises inside to the surface, hence the dampness.
By the way, I already wrote how I did it. So, the walls of the foundation from the inside also need to be covered with mastic for waterproofing. So that moisture does not "rise" on them.
Bad ventilation. In our usual climate, there will always be moisture (in the air, in the ground). If ventilation is not arranged properly, then this moisture will not be vented from under the floor, hence the feeling of dampness, mold, fungus, etc.
It is on the elimination of these causes (or rather, the minimization of their influence) that you need to direct your efforts.
I note that I have the opportunity to crawl under the floor, because. it is raised above the ground, albeit not very high. It just allows me to do something. The second thing I have provided is hatches in the floor through which you can go down. But what I didn’t do (but I could have done) - I didn’t remove the layer of black soil from the ground under the house, I didn’t pour expanded clay. It is said that this could improve the moisture situation in the underground.
So, what can be done if there is dampness, moisture and mold under the floor
The activities are listed below, but it is not necessary to do them in the order that are given here, and you can not do something at all if the effect is achieved without them.
1. Put polyethylene on the ground
It is better to take thick polyethylene with a thickness of 150 microns or more. In theory, it should protect against evaporation of moisture from the surface of the earth and prevent plants (if the fertile layer is not removed) from germinating. Polyethylene can be replaced with roofing felt. But crawling under the floor on roofing material is much less comfortable. Another option is vapor barrier (type C or D), especially since, as a rule, it remains during the construction process.
Polyethylene is taken in a roll and rolled out so that it overlaps, i.e. so that the pieces overlap each other by 15-20 centimeters.
There is one more observation - moisture can not only come from below, from the soil, but also condense from moist air. As a result, puddles will appear on the polyethylene (roofing material), which cannot go into the ground. You can only get rid of them a) by piercing a hole and letting water into the ground, b) due to normal weathering, simply speaking a draft .. So covering the surface of the earth without ensuring proper ventilation (see item 3) is not very good idea which may even make matters worse.
2. Get rid of mold if it has appeared inside under the floor
Like I said, I got mold.
Trying to cover wooden surfaces something like tar gave nothing. Then I bought an anti-mold (I think it was Neomid), took a Zhuk sprayer (this is where you pump air, and then, like from a spray gun, you spray everything you need under pressure - boards, trees, bushes, etc.), climbed with it under the floor and sprayed all the boards from below.
Yes, do not forget the respirator and even in it control your well-being without interfering under the floor!
If the mold does not disappear immediately, the operation will need to be repeated. Pay attention to choosing a sprayer that is not small, but not large either - it will be more difficult to crawl with a large one. And, of course, you need to provide yourself with protective equipment - goggles, a mask. And (important) - make sure that air enters under the floor, taking breaks in time (again, see paragraph 3.) so as not to suffocate there.
3. Provide ventilation under the floor
Make additional holes - vents in the foundation. This key moment to ensure ventilation, so that moisture and dampness are ventilated from under the floor.
It is clear that it is necessary to provide ventilation when pouring the foundation, in my case this was done. But it turned out not enough.
There are norms and formulas for calculating the number and area of products, you can find information about this on the Internet.
I will note that construction teams, as a rule, do everything without taking these norms into account and, in general, they seem to have spat on such norms and rules.
In general, in my case, the foundation was a rectangle with a wall in the middle and a part attached to it under the porch-veranda. And there were only three vents in it with a diameter of 110 mm.
I solved the problems simply - I invited specialists with the installation diamond drilling, which in a couple of hours added to me several products in the foundation with a diameter of about 120 mm (although the cost of each hole came out about a thousand rubles).
The diagrams show what was and what happened to the vents in the foundation.
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It should be noted that after these additions, a breath of wind was already noticeably felt under the floor. Although, now I would make even more products - I could add through holes also across the long side of the house.
4. Make a blind area
Perhaps the main event after airing to get rid of dampness under the floor is a blind area along the entire perimeter of the foundation. The further we divert water in the ground from the foundation, the less it will pass under the foundation into the house.
If there is a lot of water and the blind area does not save, you will have to make additional irrigation ditches in the ground. The general idea is this - water from the house, from the walls, from the roof, and simply from the rain along the blind area goes away from the foundation and falls into a groove or pipe specially made along the blind area, which can be hidden underground. And then it flows away somewhere far away to the side. Do not forget to provide the desired slope of such drainage.
By the way, a relatively simple blind area can be made without pouring concrete, using a profiled membrane, this video shows how:
The next photo shows a fragment of the foundation, which shows two options for closing the vents (they are different, because the vents were made in different time and turned out to be of different diameters), plus not yet brought to finishing blind area from the same profiled membrane:
5. Clay Castle
Moisture and dampness can pass under the foundation not only along the surface of the earth, but also inside, along the ground. This is especially true in cases where a plot with a slope, and even the ground under the floor, is obtained below the level of the surface of the plot. Water from rain or melting snow in the spring naturally passes under the foundation strip and rises to the surface inside the house, under the floor. As a result, the floor is damp and damp. In this case, the usual blind area will improve the situation, but it may not completely exclude water. Irrigation ditches may seem too cumbersome and difficult to arrange. Try the following.
To exclude such a path of moisture penetration under the house, they arrange the so-called "clay castle" - that is, they make a barrier to water in the ground from rammed clay. If this is not done directly in front of the foundation tape, then it can be done after the blind area. We dig a narrow ditch along the area to be strengthened to the depth of the clay layer (in our territories it is usually within 50 cm) and fill in the clay there, ramming it.
Instead of clay, you can use the same membrane - just install it vertically and order it. Thus, forming top layer soil, a wall is formed that does not allow water to pass through.
It is clear that these activities are carried out where the soil itself consists of such parts as the upper fertile (water-permeable "chernozem") and the lower, clayey and impervious to water.
6. Make gutters
Another important point, which allows you to significantly reduce dampness around the house (even if there is already a blind area) - these are gutters. If you still do not have gutters on the roof, then they must be done. Then the water from the roof (and its in rainy weather a lot) will go away from the house along the gutters.
7. Protect the floor boards from below from moisture with a vapor barrier
Another additional option, which I have not tried yet, allows you to protect the boards from below from dampness and moisture evaporation from the ground.
This option was suggested in the store - buy a vapor barrier film (type B), for example, isospan B, and attach it to the boards from below. Thus, the boards will be protected from evaporation from the surface of the earth, they will not get wet and moldy.
To ensure ventilation at the same time, the vapor barrier must be attached with sagging, this will ensure the movement of air between the film and the boards.
Which side to make the film down - smooth or rough? I will say unequivocally that she does not let steam through either way. Roughness is designed to ensure that the smallest drops of moisture accumulate on uneven surface, collected in large drops and eventually fell back down. Thus, it is better to do the rough side down, and the smooth side to the boards.
However, you won’t have to protect the boards from moisture if you don’t collect moisture at all. But if all the measures have been taken, but it was not possible to completely get rid of moisture, then this point may become the last line of defense.
A note after the expiration of time: if it is difficult and time-consuming to make a vapor barrier from the bottom of the boards, spit on this matter - it seems that there is not much sense in this.
By the way, are the boards impregnated with biosecurity?
In theory, all the boards of the subfloor should have been treated with biosecurity before installation. Note that this does not prevent mold from forming on top of the boards. But if biosecurity was not done at all, processing must be carried out. Be sure to use a respirator and be extremely careful there under the floor, being as little as possible in the underground space.
That's probably all. Should work. If you can offer your ideas, materials and actions to get rid of dampness under the floor - send it to stroim@site for publication here.
P.S. What if nothing helps?- Try forced ventilation. In shops where they sell all sorts of fans and ventilation pipes, you can buy a fan - from the simplest one, which is placed in the bath at home, to more powerful ones. You can try the simplest one, but it will be of little use (although, for small areas The effect will also be noticeable after a day or two of work). Insert a fan into the hole in the foundation from the inside, so that it draws air out, make an extension cord and turn it on for long time. Can also be placed underground heat gun and try to dry it. It is clear that you will not turn it on all the time, only for a while and not forgetting about electrical safety in a damp room.
P.P.S Once again, I would like to draw your attention to the fact that it is worth arranging hatches in the house during the construction of the floor. And in such quantity that it was possible to climb through them into the desired part of the room. However, remember that in winter these hatches will require insulation, so do not overdo it.
Insulate the soil under a heated house- an extra waste of effort and money, since basically the cold penetrates into the underground space through the basement of the building. Therefore, for floor insulation wooden house First of all, it is necessary to arrange the insulation of the basement of the foundation. Then cold air will not penetrate under the floor, and cool it. Note that our ancestors in the villages did not insulate the floors, but walked barefoot or in socks at home. This is because the houses had dams, which are needed not only to sit on them and husk seeds. In addition, to insulate the basement, and hence the floors, it is possible to add soil or slag and inside foundation. Such insulating bedding is carried out along the outer walls under the floor to a width of up to one meter and a layer thickness of 250-300 mm.
During reconstruction floor insulation it must be borne in mind that the height of the underground must be at least 500 mm. Ventilation of the underground space in the summer season is carried out through vents in the walls of the basement with a size of 200-250 mm, which are located at a distance of 4000-5000 mm from each other on all sides. The wetting of the water pipe and the wall from it indicates that the ventilation of the underground is not at the proper height, which is why the temperature and humidity conditions are violated in it. And when high humidity air in the underground, moisture vapor settles in the form of condensate on cold pipe. In the cold autumn-spring period of the year, the vents should be closed, or rather, plugged with a plug made of heat-insulating materials.
In wet soils, it is necessary to install a waterproofing layer underground, which can be made of crumpled clay, concrete, polyethylene film and other materials, and the surface level of this layer should not be lower than the ground level outside the building. In this case, the upper surface of the soil in the underground must be freed from the vegetation layer and cleared of debris.
For floor insulation, the internal space between the beams is filled heat-insulating material, for which it is best to use non-combustible heaters based on mineral wool from glass or basalt fibers. Usually, products in the form of mats are used for this purpose, which are laid on top of the rough flooring.
The use of polystyrene foam and similar materials from the inside of the premises as a heater must be approached with caution. Almost all of them, if they do not burn, then support combustion, while releasing toxic substances, which is fraught with extreme situations death or loss of health.
Of course, you can choose something from the local inexpensive materials: such as dry coarse sand, sawdust or slag. Just keep in mind that they must first be prepared: treated with an antiseptic, dried and mixed with fluff lime to protect the backfill from breeding rodents in it. At the same time, it should be at least 10% of the volume of backfill material. The mixture is thoroughly mixed until the composition is completely homogeneous. For more uniform mixing of organic materials with fluff lime, all components are poured onto a wooden or metal shield and turned over with shovels until completely mixed.
When the floor structure is insulated with local materials, the black floor is smeared with clay lubricant with a layer thickness of 15-20 mm, on which, after drying, dry coarse sand, sawdust or fine slag is poured to a height slightly above half of the beams. Sand or slag is poured with a centimeter layer of liquid lime mortar, dry well and only after that lay the boards of a clean floor.
When using local backfill materials, attention should be paid to their toxicity. If these materials are not tested for toxicity, it may turn out that you, without suspecting it, are planting an environmental bomb in the design of your home, which can subsequently affect the health of family members. To prevent this from happening, it is best to use proven insulation materials, the quality and safety of which is guaranteed by the relevant certificates.
A vapor barrier layer is laid over the insulation to protect it from moisture vapor. It should be noted that an air gap must be left on top of the vapor barrier layer, and at the corners of the rooms it is necessary to provide ventilation holes, covered with bars. In small rooms, holes should be in two corners diagonally, and in large rooms - in each corner. In addition, at the top of the beams, after 500-600 mm, several cuts should be made with a depth of no more than 20 mm. This should be done for free air circulation in the underground space. Instead of ventilation holes with gratings, special skirting boards can be used, and a gap of 15-25 mm should be left between the floor boarding and the walls. In addition, this gap is necessary for the soundproofing of the flooring.
All wooden structures floors are made of dry wood, the moisture content of which should not be higher than 18%. In addition, when installing plank floors, measures must be taken to prevent infection of wood by woodworms, house fungus, rot and mold. Therefore, the floorboards from the back, and the subfloor boards, the lower crowns of the house, beams and logs from all sides, must be treated with antiseptic compounds. The distribution network has both ready-to-use protective equipment and “semi-finished products”, which should be prepared strictly according to the instructions attached to the package.
Added: 05/29/2012 20:38
Forum discussion:
Is it possible to put insulation and waterproofing directly on the ground, and then put nothing on the floors at all? The ventilation in the underground-basement seems to be normal, but the wall near the water pipe and the water pipe itself are always wet in summer.IN general design extensions such that everything was done on metal posts dug in and concreted with patches into the ground. The frame and the walls themselves were attached to these posts, but there is no foundation as such. The floor used to lie there on parole - somewhere iron, somewhere pebbles, bricks were placed under the logs. More precisely, there were not even lags, but they were blinded from what was - somewhere a healthy beam, somewhere a wide board, somewhere in general emptiness and everything fell through. In general, everything has rotted for a long time and understands quietly. Since I did not want to do anything. And I haven't figured out how to do it right yet.
In general, there were two long rails, and a pipe as supports. It is planned not just to put them on the ground, but to put them on brick columns, or small patches filled with concrete. And then these platforms are somehow adjusted in height to one level, laying bricks or pieces of wood of the required thickness.
Lay these rails parallel on them, and lay logs across them.
Only at first I found on one site that for the floor you need a beam of 150 by 100, preferably, and there are already boards on it. And I planned to lay these bars in increments of 1 meter
On another site yesterday I read about plywood flooring. And they write that optimal size lag 40 by 100 mm. And they are placed in increments of 40-50 cm.
Well, 40 cm may be too fat, but about this option, to take thinner bars like theirs, and put them more often - in increments of 50 cm - I now think.
But they lay their floors on concrete slab. And there is a support almost over the entire surface of the floor, and I only get at three points - the ends of the beams are on the rails, and the pipe is round 4 meters in the middle, as a third point, so that the logs do not bend much. Will such a section be enough for me, given that the distance between the points will be slightly more than 2 meters?
Or not bother with these rails, and make posts more often?
How did who do it?
And the second question, since the ground is bare there, and the wind is whistling, blowing through everything, it is necessary to somehow make waterproofing.
In general, now I decided to start pouring a small tape of "foundation" already under existing walls. It’s not very deep there to the sand - it’s 20-30 centimeters deep - it’s easy to remove the layer of earth to the sand, and cast such a narrow tape - about 10-15 cm wide right under the wall, so that rainwater from the street, from the roof, did not flow under the house, under this floor. And then I’ll start to make something inside. Maybe you need to lay roofing material on the ground? Or will it be dry anyway if the cracks from the street are closed on all sides with this tape?
I want the cheapest economical option, but also so that in 5-10 years you don’t have to redo it, and don’t regret that everything is already screwed on, the partitions are standing, and you need to disassemble the floor of the house. To redo these floors.
blows everything
the cheapest option is to lay foundation blocks and make a floor on them
think, if there is air exchange under the floor, is it necessary to do something at all there ....
but if you close the vents with tape, then do not forget to make ventilation holes
the cheapest option is to lay foundation blocks and make a floor on them
Therefore, I am inclined to the option of casting these platforms on the spot. It will be the same concrete. With a shovel, I'll somehow master it. I have filled in small volumes before.
Well, the foundation blocks are both expensive and very heavy. Here, either equipment is needed, or 10 healthy men who will help turn them around. And delivery too headache. And there's no one there to help me. Or one everything or a brother for a day, at most, something heavy will drive up to help drag it.
Therefore, I am inclined to the option of casting these platforms on the spot. It will be the same concrete. With a shovel, I'll somehow master it. I have filled in small volumes before.
you don't think about it
block 20*20*40 weighs about 30 kg.
you don't think about it
block 20*20*40 weighs about 30 kg.
And I don’t know what thickness of reinforcement to take either. I'll probably take 8mm.
And, well, if they are ... We need to see how much they cost on average. And then, the joints between them all the same I have to cover up. Water will flow through these joints - 100 percent, and then there will be little sense from this design. She will not save from frost, only from the wind?
And the earth also has such a property - it walks when it freezes and thaws. I think that these blocks without their reinforcement will rise and fall on their own. It will be a disaster, not a foundation.
I want to take long rebar - along the length of the entire wall of the house, and put them into this tape two bars at a time. So she will walk at least as a whole, and not in parts. Although about two bars - I really want it - how much is needed - I don’t know for sure. Maybe one is enough for the eyes.
And I don’t know what thickness of reinforcement to take either. I'll probably take 8mm.
close the plinth with a flat rivet
they cost 50-60 rubles probably per piece.
I meant to use these blocks - as linings for logs, and not to lay a tape of them ...
under the blocks, it is natural to pre-prepare the place - remove the soil, and make a sand and gravel cushion, on the roofing material block, on the logs roofing material
close the plinth with a flat rivet
And with what step are the lags themselves laid?
Understood. There will already be crushed stone, there is sand there. We need to see how much they cost. So it can be and how to stick a column, put it on the end? Or are they placed horizontally?
Well, this is not the biggest problem - I will not find these blocks - you can cast them on the spot. But how far apart should they be? If, as I thought, at the beginning, at the end of the room and in the middle, then the distance between the supports will turn out to be 4.7 in half = 2.35 meters. This is fine? Or should I put more of them? What section should the beam be at such a distance so that it doesn’t break, and I don’t need a large stock - I don’t plan to keep elephants there. The maximum will be large heavy cabinets with all sorts of junk, a sofa. Internal partitions will also be hanging on supports, that is, not tied to the floor.
And with what step are the lags themselves laid?
but it depends primarily on what the floor will be made of and what load it will be ...
well, you didn't write the floor area))
I am a supporter of using a log 50 * 150 after 60-70 cm.
but it depends primarily on what the floor will be made of and what load it will be ...
Just ideally, I would generally make two points of support and that's it. The middle columns, after all, can also rise and fall over time from winter to summer, and the floor will either sag or bulge with a hump. Or just the lag will not rely on all points.
50 to 150 ... And they are placed, as I understand it, on the edge? Or flat? (with a narrow part standing or lying down?) I just watched one video - they did the opposite. After that, I got completely confused.
And how many supports do you have under these lags? What length were they?
Just ideally, I would generally make two points of support and that's it. The middle columns, after all, can also rise and fall over time from winter to summer, and the floor will either sag or bulge with a hump. Or just the lag will not rely on all points.
room dimensions?
under each block, as I already wrote, make a pillow to minimize heaving
room dimensions?
naturally, a lag is placed on its side, I try to have fulcrum every 2 meters, sometimes 1.5
under each block, as I already wrote, make a pillow to minimize heaving
The total length of the room is 4.7 meters, (lags are planned for this length) the width is different everywhere - the beginning is 5.5 meters, then it narrows to 3.5
i would put 4 blocks under the lag
So that's probably what I'll do.
Flat slate, of course, is also an option - to close the base. But I don't know how long it will last. I've never seen anyone close them down. And then I looked at the dimensions - 1.5 meters is the maximum length. Again, you have to put the pieces together somehow. Or overlap in two layers so that water does not leak.
What's better to insulate? I read - they pour expanded clay. But the minimum layer thickness should be 10-15 centimeters. If we take my area, it comes out according to the most conservative estimates 5.5 * 4.7 * 0.1 = 2.5 cubic meters. 1 cube of expanded clay seems to be 1800r = 4650r - just pour it on the ground to nowhere. It will be painfully fat. We need to come up with something more economical, and to be effective. The room is planned as residential heated. Gas is supplied there. And no one will allow to drown the street. (therefore, again I think that slate is not a very good option)
The main thing at the lag is height. Span length (from support to support) for 150mm - no more than 2.5 meters. Well, 3, but they will already play a little. That is, for 4.7 - two spans, three pillars (stones, curbs).
Or you can knock down two 100x150 (to save on the vertical, you can take 50x150) with the letter T "upside down". According to the loads, it should be enough for 5 meters (I don’t remember exactly, I need to raise the formulas, see the indicated sites). Put two supports at a distance of 4-4.2 meters (an overhang near the wall, taking into account the thickness of the column, will not play a role). The lower beam can just be used as a shelf for the subfloor. Put such logs at a distance of 70-80 cm (between the planes). Here, between the subfloor and the finishing floor, expanded clay can be used.
Again, as an option, start up a normal concrete strip foundation on a sand cushion just below the frame (to compensate for accidental movements) with a ledge inward. And put logs 250 mm high on it (the same prefabricated ones).
Many descriptions of floor options, logs, foundations, etc.
You can put logs 50x150 on the edge. Or make packages. Or "channel". Depends on span length available materials, floor coverings.
As linings, you can take fragments of curbs. A couple of years ago there was a lot on the edge of the ravine behind Stroydepo and to the right after the cafe. They poured in from all over the city. Accordingly, enterprising people recruited for themselves. Maybe now there is.
Stones under the logs can be poured directly into the level into the formwork from boards and / or plywood using a hose with water. Well, or immediately formwork to the level to make and pour along the edge.
The main thing at the lag is height. Span length (from support to support) for 150mm - no more than 2.5 meters. Well, 3, but they will already play a little.
The foundation can be made with a heap of flat slate and sand. About half a meter will already be good. The slate here is just a limiter. Insulation - sand. Products, for example, from sewer pipe. Through two sheets of slate and sand.
If everything around is flooded with water, then without normal drainage, all this is useless. We must start with it. Either horizontally divert or drill drainage wells.
I also think so - cast the columns immediately at the level into the formwork, so as not to suffer much with the fit. I strained with the boards there - the good ones all went to work, but I don’t want to leave rottenness in the ground, and I don’t know if the required number of boards will be typed into the formwork. But the old slate removed from the roof, heaps. I think it is suitable for formwork, so that it can be left there with the ends, and not removed? I just never tried to drink. I want to try to cut it to size with a grinder. Well, if it is pricked, you will have to quit this idea.
at 30.4.2014, 15:15
Answer
3-4 vertical bars 8-12 mm in diameter. Very desirable from defrosting.
You can drill holes, stick round ventilation ducts (150mm) there as formwork. The columns will be just a feast for the eyes. But more expensive, of course.
Read on the Internet the rules for cutting slate. There it is necessary to wet the saw line. And there are still nuances.
Oh ... I remembered, I still have an asbestos pipe. (somewhere about 20 cm in diameter) The truth is small. It is not enough for many columns. But this is an idea. I saw this. Pour it in and that's it. But again, it probably doesn’t matter how the slate is sawn. Need to try.
And why is there, in fact, fittings inside the pipe? It seems to me that it will be strong. Well, if the scraps remain, of course I will shove them. And for such a small diameter, 4 rods are probably overkill. One or two is enough.
The wooden floor on the logs allows you to do without without use reinforced concrete floor or device of another concrete base , the cost of construction of which is quite high.
Efficient ventilation of wooden on logs in a private house - a necessary and indispensable condition for the reliability and durability of the structure.
Wooden floor on joists
The figure shows a variant of the construction of a wooden floor on logs in a private house with an underground space.
The space under the floor is formed due to the fact that the logs are laid on fairly high columns of brick or concrete blocks. This design allows you to raise the floor level of the first floor with a minimum amount of backfilling with soil in the basement space.
Here, the plinth and plinth space under the floor are outside, outside the heat-shielding shell of the house, and will be cold.
To ventilate the underground space in opposite outer walls, above ground level, air vents are made - through holes closed with a metal mesh to protect against rodents. The same holes should be in the internal load-bearing walls.
The movement of air under the floor is mainly due to wind pressure.
In winter, there is a danger of soil freezing in the underground space, which can lead to the movement of the floor relative to the walls on heaving soils.
To prevent freezing, it is recommended to close the vents for the winter, and insulate the base.
However, the deterioration of ventilation as a result of the closing of the vents leads to the accumulation of moisture in the insulation and wooden parts - to a decrease in thermal resistance and durability of these elements.
I must say that such an underground space device has been used in private construction since ancient times. The design was not originally designed for use effective thermal insulation gender.
In houses with poor thermal insulation of the floor in winter, part of the heat from the room penetrated into the underground space and heated it, preventing freezing, but increasing heat loss.
Modern thermal insulation of the floor practically blocks the flow of heat into the underground from the premises.It is possible to prevent the freezing of the subfloor only by saving the heat of the earth.
With modern requirements for energy saving, a cold underground ventilated through the air is not the best option. It is still used rather by inertia.
The scheme of effective ventilation of the subfloor in the basement of a private house through exhaust channelTo ventilate the underground of a private house, a cottage, it is beneficial to use effective ventilation through the exhaust channel. This ventilation scheme is the only the right option for a house with an insulated basement or with a basement.
How to make a wooden floor on posts
In old books and building regulations, you can find floor designs on posts using NOT effective heat and waterproofing materials.
Modern floors on logs in a private house do this
Support posts are laid out of ceramic bricks or concrete blocks. The distance between adjacent posts along the log (span) is recommended to be no more than 2 m. The base of the column can be a layer of compacted crushed stone 50-100 mm, spilled bituminous mastic. Or instead of mastic, a waterproofing film is used.
The top of the columns is leveled in one level with a solution. With a solution thickness of more than 3 cm. a masonry mesh is sunk into the solution. The top of the columns is covered with a sheet of waterproofing material.
Wooden beams-logs are laid on the waterproofing layer. The distance between adjacent beams-lags (step lag) is determined by their cross section, as well as the bearing capacity and rigidity of the overlying layers of the floor - lathing, subfloor, finish coat. Usually they take a step convenient for laying between the lags of standard mineral wool insulation boards, about 600 mm.
For the above lag step and span between the posts, taking into account the thickness of the insulation and the crate, with normal floor loads, the lag section is sufficient 100-150x50 mm. A galvanized steel mesh is attached to the bottom of the logs lying on the posts. Instead of a grid, you can nail boards into the run-up, slats with a thickness of at least 20 mm.
On top of the mesh (boards) and the log, a windproof, highly vapor-permeable film is laid.
This film prevents makes it difficult for the particles of the insulation to be carried away by the air flow (formation of dust), but does not prevent the evaporation of moisture from the insulation and wooden parts.
A panel of a windproof vapor-permeable film is laid on top, across the log, and lowered on both sides of each log until it stops in the steel mesh so that a tray is formed between the logs. The film is nailed with a stapler to each side of all the logs.
In the formed channel between the lags, a mineral wool insulation is laid on the windproof film. You can do without a windproof film if you use special insulation boards with a compacted windproof layer for the bottom layer.
How to determine the thickness of the floor insulation
The thickness of the floor insulation is chosen according to the calculation, providing the normative resistance to heat transfer R = 4-5 m 2 about K / W. If the basement is not insulated, then the thickness of the thermal insulation of the floor is determined from the condition that the temperature of the space under the floor is equal to the temperature of the outside air. The recommended thickness of mineral wool insulation in this case is not less than 150-200 mm.
For a house with an insulated foundation and plinth, the thickness of the floor insulation can be reduced so that the sum of the heat transfer resistances of the plinth + floor is no less than the norm (see above).
How to calculate the thickness of the thermal insulation of the floor (ceiling)
A crate of bars with a thickness of at least 50 mm is laid across the log. Between the bars of the crate place another layer of insulation. Such a two-layer construction of insulation provides insulation with overlapping cold bridges through the logs. The distance between the bars of the crate is chosen within 300-600 mm., a multiple of the width of the subfloor slabs.
Such a two-layer construction of the floor base (logs + lathing bars) allows you to conveniently place both insulation boards and floor covering boards (DSP, plywood, etc.).
The insulation with the crate on top is covered with a vapor barrier film. The joints of the film panels are sealed. The junctions of the film to the walls are connected to the waterproofing of the wall and the same is sealed.
It is recommended to choose the thickness of the lathing bars by 25-30 mm. greater than the thickness of the top layer of insulation. This will allow, by lowering the film on both sides of each lathing bar, to create a ventilated gap between the vapor barrier film and the floor covering.
Vapor-thermal insulation with foam
Instead of the top layer of insulation and vapor barrier film, it is more profitable to lay penofol - foamed polymer coated aluminum foil, thickness 10 mm. (produced under other trade names).
Penofol must be laid with the aluminized side up, towards the ventilated gap, across the bars of the crate and lowered on both sides of each bar. After that, penofol is nailed to each side of all the bars with a stapler so that a gap of 3-4 is formed between the aluminized surface and the floor tiles. cm.. The joints of the foam panels are sealed with aluminized adhesive tape. A layer of foam foam will provide heat transfer resistance equivalent to a layer of mineral wool with a thickness of 40 mm., and the necessary vapor permeability.
Subfloor boards are attached to the lathing bars over a vapor-tight film or penofol. Instead of boards, slabs are more often used: cement-bonded chipboard (thickness> 22 mm.), plywood (> 18 mm.), etc. Sheets, plates are placed with the long side on the bars of the crate. Spacers are fixed under the short side between the bars of the crate. All edges of the laid sheet must have a support under them - a bar or spacer.
Use as foam insulation polystyrene boards Not recommended. Such boards serve as a barrier to moisture, which is always contained in the wood of the floor. By preventing the release of moisture from the wood, foam insulation reduces the life of the wooden parts of the floor. In addition, mineral wool insulation, due to better elasticity, adjoins the logs more tightly than polystyrene.
To protect the underground space from ground moisture, it is advisable to cover the entire surface of the soil with a waterproofing film (and not just under the posts, as in the figure). The joints of the coating panels are sealed. The adjunction of the film to the walls must be connected to the waterproofing of the wall and also sealed. The floor posts lie directly on the film.
As a result, we get a ventilated underground space, limited by sealed shells - from above (vapor barrier) and from below (waterproofing).
Such an underground space protects the house not only from moisture and cold, but also from penetration into living quarters.
Floor along the lags on the intermediate walls
IN modern designs beam-lag floors are located at a small distance from each other, which allows the use of lumber of a smaller section, and hence the cost, and it is also convenient to place insulation boards.
Instead of brick columns, it can be advantageous to lean the logs on intermediate walls laid out across the log with an interval of about 2 m. Bricks or blocks in the wall are laid in a honeycomb laying method half a brick thick, leaving increased gaps of 1/4 bricks in vertical joints to ventilate the underground space. If the wall has a height of more than 0.4 m., then at least every 2 m. the length of the wall, lay out pilasters - brick-thick columns, to increase the stability of the wall.
If the step lag is not more than 600 mm. and span less than 2 m., then the cross section of the wooden log is enough to have 100x50 mm.
Wooden floor on the ground on logs
Another version of the wooden floor along the logs in a private house is shown in the following figure:
Here, unlike the first option, the floor level is raised to the required height by backfilling the basement with compacted soil.
Floor ventilation is carried out due to the movement of air under the action of the draft of the ventilation duct.
Warm air is taken from the room and through the ventilation holes in the baseboards and the gap between the subfloor covering and the wall enters the space between the joists. The air then enters ventilation duct.
To ensure ventilation of the underground space, skirting boards with holes are used or skirting boards are installed with a gap between them and the walls.
In order for the air to move more or less evenly under the entire surface of the floor, the gap for the passage of air is made of different widths - the farther from the ventilation duct, the wider the gap (2 cm.). Near the ventilation duct, holes in the baseboards and gaps between the wall and the floor covering are not made (or the gap is sealed with tape).
It is important to understand that in this ventilation option, unlike the first, the underground space is located inside the heat-shielding shell of the house, and must necessarily be warm. The outer shell of the subfloor must have a resistance to heat transfer no less than the wall of the house. Otherwise, the receipt warm air from the room can lead to condensation on the parts of the subfloor.
Make a layer of bulk soil thicker than 600 mm. Not recommended. Soil is poured and carefully rammed in layers no more than 200 thick. mm. It is still not possible to compact bulk soil to the state of natural soil. Therefore, the soil will settle over time. A thick layer of loose soil can lead to too much and uneven subsidence of the floor.
The waterproofing film is laid on a leveling layer of sand with a thickness of at least 30 mm. The joints of the film panels are sealed. The junctions of the film to the walls must be connected to the waterproofing of the wall and also sealed.
Thermal insulation is laid on waterproofing.
In this option, it is better to use polymer insulation boards - polystyrene foam (polystyrene foam). The thickness of the insulation is enough 50-100 mm., since the temperature of the soil under the house is always positive.
If the walls and basement of the house are not insulated, then along the outer walls to a width of at least 800 mm. a thicker layer of insulation should be laid, 150 - 200 mm.
At a house with multilayer outer walls with insulation outside, in order to exclude a cold bridge bypassing the wall and floor insulation, must be insulated outside(see the figure in the first part of the article).
The floor logs lie on low brick or concrete block linings.
If slabs of extruded polystyrene foam (XPS, penoplex, etc.) are used as thermal insulation, then the logs can be laid on linings cut from these slabs.
between insulation and wooden lags floor should provide a gap of 3-5 cm. for free air movement.
By building regulations there is one restriction on the device floor. Since the space under the floor is ventilated through the exhaust duct natural ventilation, then it is forbidden to finish the floor covering from combustible materials: from boards, parquet boards and shields, etc. Or, a non-combustible base should be provided under them, for example, a prefabricated screed made of plasterboard, gypsum-fiber sheets or a draft floor made of cement particle boards.
In this option, the logs and other floor elements are in better humidity conditions than in the first case.
In this design, the ventilation duct serves to ventilate not only the underground, but also the premises of the house. About what needs to be done to save the heat emitted by the ventilation system,
Floors, soils and foundations
Floors on the ground are not connected to the foundation and rest directly on the ground under the house. If heaving, then the floor in winter and spring can "walk" under the influence of forces. To prevent this from happening, the heaving soil under the house must be made not to heave. The easiest way to do this, and the underground part
The design of pile foundations at bored (including TISE) and screw piles involves the device of a cold base. Warming the soil under the house with such foundations is a rather problematic and expensive task. Floors on the ground in the house on pile foundation can only be recommended for non-heaving or slightly heaving soils on the site.
When building a house on heaving soils, it is also necessary to have the underground part of the foundation to a depth of 0.5 - 1 m.
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| In a house with external multi-layer walls with insulation on the outside, a cold bridge is formed through the basement and the bearing part of the wall, bypassing the wall and floor insulation. |
