"Aeroreflexduk" or building plastic for insulating crawl space?

[WibAir]

Hello,

We have moisture and mold problems in our crawl space, and various companies have provided quotes and solutions. The moisture partially comes from the ground, and it is recommended to lay a membrane throughout the foundation to block moisture in combination with a dehumidifier.

One company has spoken highly of using a so-called "aeroreflex membrane" in aluminum (6mm) instead of regular building plastic. The argument is that it will reflect heat from the house, and the entire foundation will become significantly warmer (up to 10 degrees warmer according to them!!). The heat is supposed to make the dehumidifier work more efficiently and improve the climate of the house.

Does anyone have experience with this type of membrane?
What do you think, could it be as good as they claim?

Grateful for advice and opinions!

 

[Bosch]

Hello

I have no personal experience with aeroreflex fabric but am familiar with the principle. The idea is that the more you increase the temperature, the more the relative humidity decreases, provided there is no external moisture addition. What type of dehumidifier is it? Sorption or the safety guard?

When I renovated my crawl space, I chose to lay a vapor barrier & concrete cover mat (like sleeping pad) in combination with a sorption dehumidifier to provide the space with a better climate. But if it's going to be feasible for a company to do it, you probably need to calculate the price difference and heat loss. If you intend to use the safety guard, it’s probably money well spent unless there is a very large price difference since it works with heat.

First post on the forum, by the way.

 

[holmberg87]

I don't think you'll get much warmer with that cloth.
Use construction plastic and as mentioned above concrete covering mat if you want to insulate a bit. If they are talking about heat, they might want to use a condensation dehumidifier which doesn't work at colder temperatures.

I have construction plastic in my crawl space.

 

[WibAir]

Thank you for the answers. Sorption dehumidifiers have been offered.

The sellers refer to a study from Chalmers which I looked into. It seems to be a minor study as a thesis project; http://studentarbeten.chalmers.se/p...isolering-aluminiumfolie-med-olika-funktioner

The study states that it can work well in walls as a complement to wool and as a replacement for regular vapor barriers. Not sure if it can be applied to the ground.

 

[Lars48]

Does anyone have experience with this type of tarp?
What do you think, could it be as good as claimed?

Grateful for advice and opinions!

Read the thesis you've linked. It looks good according to the experiments. It's worth a try if you trust the report.
I am personally against all types of dehumidifiers in crawl spaces due to the fire risk.
What is important for an affected crawl space is to counteract rising moisture from the ground. For example, fill with washed gravel, plastic cover. One important thing is a condensation barrier on the ground and the walls. In the past, stone wool insulation was used. If the aeroreflex tarp works as a condensation barrier, then that's good.

 

[WibAir]

Read the thesis that you have linked. It looks good according to the experiments. It's worth trying if you can rely on the report.
I am, however, against all kinds of dehumidifiers in crawl spaces due to the fire risk.
What is important for an affected crawl space is to counteract moisture rising from the ground.. For example, fill with washed gravel, plastic wrap. One important thing is a vapor barrier on the ground and walls. In the past, stone wool insulation was used. If the aeroreflex fabric works as a vapor barrier, then that's good.

Thanks for the response, Lars. I'm unsure myself how to interpret the thesis.

Regarding the fire risk, it's always there theoretically, but it mostly seems like there are two models that have had issues historically after a quick Google search I did.

The wood in the subfloor is very damp and even if we insulate and no new moisture comes in, I assume you want a dehumidifier there to dry out the wood initially?

Does anyone else have experience with this?

 

[holmberg87]

Yes, you must dry out the wood to start with. And it's probably not a particularly high fire risk, I haven't read about any example.

 

[Axbard_89]

Reviving this thread. How did you decide to use construction plastic or areoreflex cloth? If you chose areoreflex cloth, do you notice a difference in the indoor climate considering that the cloth inherently warms the space?

 

[Petra13]

Those of you who have applied plastic to the foundation, have you done it yourselves or hired a company to do it for you? We are considering doing it ourselves, is it complicated?

 

[Axbard_89]

Those of you who have coated the foundation, did you do it yourself or hire a company to do it for you? We are considering doing it ourselves, is it complicated?

Hi!

I coated my foundation myself. Whether it's complicated or not probably depends on the situation.

Here's how I did it:
1. Chose between construction plastic or a concrete mat, in the end opted for the thickest construction plastic.
2. If there is soil or similar, it might be good to dig out all that is classified as organic material. (I didn’t have any).
3. Rolled it out edge to edge in the foundation, then "overlapped by 30cm" on the next layer.
4. I used stones to weigh down the plastic.
5. "Hired" my friend’s son who's in high school to lay the plastic in the part of my house where I couldn’t reach.
There wasn't plastic everywhere because it was inaccessible.

I immediately noticed that the humidity dropped by 10-15 RH on average (I have a meter that starts my dehumidifier).
As a cherry on top, I lowered the RH value for when my dehumidifier should activate to 58% instead of 65.
The reason I lowered my RH for when the dehumidifier should start is because I think it's good if it runs a few times a day during the period when moisture is worst in a crawl space. Due to the fact that I couldn’t lay plastic everywhere.

I'm now fluctuating between 48-58 in my foundation and I think it's working well!

It took a few hours in total, but I have an easy side of the foundation on one side of the house where you don't have to crawl, but on the other part, it was worse.

 

[Axbard_89]

Hello!

I insulated my foundation myself. Whether it's complicated or not is probably case by case.

Here's how I did it:
1. Decided between construction plastic or a concrete mat and ended up choosing the thickest construction plastic.
2. If there's soil or similar, it might be worth digging out anything classified as organic material. (I didn't have any).
3. Rolled it out edge to edge in the foundation, then "overlapped by 30cm" on the next layer.
4. I used stones that I placed on top of the plastic to weigh it down.
5. "Hired" my friend's son, who is in high school, to lay the plastic in the part of my house I couldn't access.
This didn't result in plastic everywhere due to not being able to reach.

I immediately noticed that the humidity dropped by 10-15 RH on average (I have a meter that activates my dehumidifier).
As the icing on the cake, I lowered the RH value at which my dehumidifier kicks in from 65% to 58%.
The reason I lowered my RH for when the dehumidifier starts is because I think it's good if it runs just a few times a day now during the period when moisture is at its worst in a crawl space. Because I couldn't lay plastic everywhere.

I now fluctuate between 48-58 in my foundation, and I think it works well!

The time spent was a few hours, but I have a favorable foundation on one side of the house where crawling isn't necessary, though it's worse on the other side.

Here's a picture of what it looks like.

 

[Petra13]

So much space you have, we have very cramped between the ground and the framework.

 

[Axbard_89]

That will definitely become problematic. But you should try to manage as best as you can. A dehumidifier might be a good idea to install.

 

[KnockOnWood]

Reviving this thread. How did you choose between construction plastic or aeroreflex cloth?
If you chose aeroreflex cloth, do you notice a difference in the indoor climate considering the cloth fundamentally heats?

About the thread starter:

 

[Petra13]

About the thread creator:
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