Insulation of the walls of a crawl space with polyurethane panels (PUR, PIR)
published: 08/09/22, 12:33
Insulating the exterior walls of my crawl space is a project that I have wanted to do for years (but as with many projects I have left it lying around) I got started this summer because I found insulation from occasion not far away which corresponded well to this site. Hey yes it's not only the trailers in life huh!
Given the conditions, I couldn't use something bio-based like wood wool, or even chemical wool (yuck)... Only "chemical" panels were possible.
There are polyurethane panels of 1200 * 2800 * 72 mm with double aluminum cover. The vendor had another small stock of 80mm TMS panels which I also purchased.
I also recycled some extruded polystyrene scraps (see photos)
After more than a month of more or less regular work, the site is finally ending very slowly (impossible to work for more than 2 hours in a row...given the physical conditions) so I'm sharing all this with you in the hope that this will motivate you to also insulate your possible crawl space!
It's a project that would have cost me several thousand € if done by a pro I presume...given the conditions...
Preliminary construction conditions:
- It is a large habitable crawl space 120 cm high. I put my wine cellar there and it serves as a warehouse (it won't be anymore now that it's healthier...except for the pinard and some bottles didn't like these too humid conditions )
- He's on a foundation slab with some dirt on it.
- It is not ventilated (with winters at -15°C or very humid, it may be better...) but it is open to the cellar via an access staircase.
- During the first years, during heavy storms water, about 10 cm, flooded the VS (there are still traces, for example on the racks of the wine cellar), I had made a good waterproof mortar there where there were cracks on the main slab and that solved the problem. But it still proves that I have hydraulic pressure under the house. And that's not very good!
- After this slab repair, I left the VS like that for years without worrying but residual humidity was blocked and caused "thermal loops" evaporation, condensation, etc... I had not done good dehumidification at the time.
- I've always had humidity inside: the walls constantly oozed. More than 10 years ago I did a water-repellent treatment and placed some hydraulic mortar where there was the most water on the ground, but that hadn't changed anything.
- As I am smarter today than 10 years ago (yes!), I finally understood that it was condensation . In some rooms of the VS, I literally had puddles of water from this condensation (see photos)
The construction stages:
I decided to start this project a few weeks ago, at the end of July when I found the insulation.
This is good given the explosion in energy prices (it probably motivated me a little unconsciously...)
A dehumidifier runs almost 24 hours inside, especially before installing the insulation, I didn't want to trap moisture in the walls behind the insulation. I must have released a hundred L's for a little over a month...
Brave granny saab who carries a few m3 of insulation without flinching (I did not exceed 80 km/h!):
A) Lathing
I made everywhere a lathing of 1, 2 or 3 cm depending on the materials I had on hand (100% recycled)...either in wood or in polystyrene...
B) Reinforcing hydraulic screed
In the wine cellar, where there were puddles (this is also where there was the biggest crack in the slab), I also laid a very small hydraulic screed (a sika-like additive) with an equalizing mortar (this brought 40 to 50 L of water more in the cellar during the installation...) to reinforce the repair of the cracks of years ago.
In the photo the screed is drying...
Some slats, I glued them on, that's more than enough, came off after the humidity rose from the screed of the wine cellar... the wood probably expanded or deformed with the grip. humidity...
C) Installation of insulation
The panels are simply glued to the slats (neoprene as for the slats), there is no effort on it and I close the top so that the air does not circulate.
In this photo, NORTH wall, I had already tinkered with (100% offcuts) a wall insulation years ago because it was the stickiest wall...given the wet floor well, 1 wall wasn't enough!
And here it was almost final on one of the corners of the wine cellar: more puddles of condensation!!
But this is normal because the ceiling part was not waterproof. Yesterday I plugged it and today it's already much better.
The wall on the right, already clogged, showed no puddles...everything came from the left in the photo! That's a pretty good sign!
I plug the "arches" of the ceiling with a small sheet of polystyrene a few cm long, I stuff scraps into it and I inject spray PU... The stuffing is to save bombs, I already have some past 4 of 750 ml...I will need another 2 to finish the job...
I'll post more photos when the construction site is completely finished a few days after the dehumidification stops.
Last thing this site is also important to reduce the heat loss of my big thermal pad which can also be a source of humidity: it is not 100% waterproof as it is a concrete tank... For those who do not yet know my solar installation with buffer:
solar-thermal / solar-house-and-high-power-thermal-solar-panels-t5283.html
Solar-thermal / thermal-solar-buffer-optimization-and-repair-t4517.html
Given the conditions, I couldn't use something bio-based like wood wool, or even chemical wool (yuck)... Only "chemical" panels were possible.
There are polyurethane panels of 1200 * 2800 * 72 mm with double aluminum cover. The vendor had another small stock of 80mm TMS panels which I also purchased.
I also recycled some extruded polystyrene scraps (see photos)
After more than a month of more or less regular work, the site is finally ending very slowly (impossible to work for more than 2 hours in a row...given the physical conditions) so I'm sharing all this with you in the hope that this will motivate you to also insulate your possible crawl space!
It's a project that would have cost me several thousand € if done by a pro I presume...given the conditions...
Preliminary construction conditions:
- It is a large habitable crawl space 120 cm high. I put my wine cellar there and it serves as a warehouse (it won't be anymore now that it's healthier...except for the pinard and some bottles didn't like these too humid conditions )
- He's on a foundation slab with some dirt on it.
- It is not ventilated (with winters at -15°C or very humid, it may be better...) but it is open to the cellar via an access staircase.
- During the first years, during heavy storms water, about 10 cm, flooded the VS (there are still traces, for example on the racks of the wine cellar), I had made a good waterproof mortar there where there were cracks on the main slab and that solved the problem. But it still proves that I have hydraulic pressure under the house. And that's not very good!
- After this slab repair, I left the VS like that for years without worrying but residual humidity was blocked and caused "thermal loops" evaporation, condensation, etc... I had not done good dehumidification at the time.
- I've always had humidity inside: the walls constantly oozed. More than 10 years ago I did a water-repellent treatment and placed some hydraulic mortar where there was the most water on the ground, but that hadn't changed anything.
- As I am smarter today than 10 years ago (yes!), I finally understood that it was condensation . In some rooms of the VS, I literally had puddles of water from this condensation (see photos)
The construction stages:
I decided to start this project a few weeks ago, at the end of July when I found the insulation.
This is good given the explosion in energy prices (it probably motivated me a little unconsciously...)
A dehumidifier runs almost 24 hours inside, especially before installing the insulation, I didn't want to trap moisture in the walls behind the insulation. I must have released a hundred L's for a little over a month...
Brave granny saab who carries a few m3 of insulation without flinching (I did not exceed 80 km/h!):
A) Lathing
I made everywhere a lathing of 1, 2 or 3 cm depending on the materials I had on hand (100% recycled)...either in wood or in polystyrene...
B) Reinforcing hydraulic screed
In the wine cellar, where there were puddles (this is also where there was the biggest crack in the slab), I also laid a very small hydraulic screed (a sika-like additive) with an equalizing mortar (this brought 40 to 50 L of water more in the cellar during the installation...) to reinforce the repair of the cracks of years ago.
In the photo the screed is drying...
Some slats, I glued them on, that's more than enough, came off after the humidity rose from the screed of the wine cellar... the wood probably expanded or deformed with the grip. humidity...
C) Installation of insulation
The panels are simply glued to the slats (neoprene as for the slats), there is no effort on it and I close the top so that the air does not circulate.
In this photo, NORTH wall, I had already tinkered with (100% offcuts) a wall insulation years ago because it was the stickiest wall...given the wet floor well, 1 wall wasn't enough!
And here it was almost final on one of the corners of the wine cellar: more puddles of condensation!!
But this is normal because the ceiling part was not waterproof. Yesterday I plugged it and today it's already much better.
The wall on the right, already clogged, showed no puddles...everything came from the left in the photo! That's a pretty good sign!
I plug the "arches" of the ceiling with a small sheet of polystyrene a few cm long, I stuff scraps into it and I inject spray PU... The stuffing is to save bombs, I already have some past 4 of 750 ml...I will need another 2 to finish the job...
I'll post more photos when the construction site is completely finished a few days after the dehumidification stops.
Last thing this site is also important to reduce the heat loss of my big thermal pad which can also be a source of humidity: it is not 100% waterproof as it is a concrete tank... For those who do not yet know my solar installation with buffer:
solar-thermal / solar-house-and-high-power-thermal-solar-panels-t5283.html
Solar-thermal / thermal-solar-buffer-optimization-and-repair-t4517.html