Crawl Space Insulation, Again :-)

2776 Views 13 Replies 8 Participants Last post by Tom M, Jan 9, 2014

Sergei

Discussion Starter · Jan 8, 2014

The project I have is all about crawl space.
Right now it is vented (just holes in the walls) and insulated with fibreglass batt.
So we faced here mold, smell, moisture and damaged fibreglass falling down from the joists. There is no furnace – The house is heated by electric baseboards.
Lot of specialist offer not-vented solutions like insulate all perimeter and remove fibreglass.

Because we never did that before I have few questions, so more experienced contractors can advise on

1. In general – is it a good idea – non-vented crawl space?
2. The house is heated by baseboards – so if we seal the crawl space it will not be heated and no or a little air movement is expected. Any potential danger?
3. If the owner install furnace later – should the crawl space be included in the system?
4. The floor of the crawl space is concrete – so should we insulate it? Or just place liner to act as a vapour barrier? Could this barrier damage the concrete? Any solutions?
5. Is there any step by step instructions on the best way to do that?

Thanks in advance for all answers!

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ScipioAfricanus

· #2 · Jan 8, 2014

What kind of trade is OXOCA?

There are many things to consider when doing any crawl space, whether vented or conditioned.
Perhaps call a knowledgeable contractor in you area?

Andy.

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Sergei

Discussion Starter · #3 · Jan 8, 2014

Hi Andy,
I will contact a few for sure but would like to get the contractortalk's users opinions as well.
There are a few opinions on this topic and the more I know the better.
Thanks.
oxoca is a mistake – forget it.

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Dan_Watson

· #4 · Jan 8, 2014

Its a shame this smells like a HO, because they are actually great questions that I am interested to hear the answers to. (not joking, this is actually a relevant topic for me right now)

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greg24k

· #5 · Jan 8, 2014

Since the crawl space existing, get rid of all the BS you got there now... make sure there is access, make sure crawl space is vented and make sure the floor, the rim-joist above is insulated properly.

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Sergei

Discussion Starter · #6 · Jan 9, 2014

Got it.

Thanks for the replies.

So, the idea is to remove Fiberglas and replace it with rigid foam or sprayed foam or combination of both … (vapour barrier on top of it ?) I mean floor(width joist), than barrier, than foam, than crawl space(air), than concrete. And do not insulate concrete, just side walls. Keep it vented as is. Right ?

One more question then: if I insulate the floor(top) Could I have problem of freezing water pipes – they are in the crawl space and no heat will come from the house any more …

Thanks !

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SLSTech

· #7 · Jan 9, 2014

Dan_Watson said:
Its a shame this smells like a HO, because they are actually great questions that I am interested to hear the answers to. (not joking, this is actually a relevant topic for me right now)

The answers vary Dan based on locale & agreed - in short for your area
1. Almost always a good idea - how close to coast are you though
2. & 3. Codes have certain requirements that must be met
4. uh no - why?
5. depends on the project, but if dry, clean, etc... remove floor insulation, air seal floor, seal up vents, insulate sides, add in code required air

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CarpenterSFO

· #8 · Jan 9, 2014 (Edited)

...

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Patsfanindallas

· #9 · Jan 9, 2014

I removed all the batt insulation on my pier and beam house because of the musty smell. Next week I'm having closed cell foam spray under the entire house. A vapor barrier was not recommended to me because it's closed cell foam.

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Patsfanindallas

· #10 · Jan 9, 2014

PS: it really sucks to remove all that batt insulation. even with a tyvek suit, gloves, hood, and goggles, it still manages to get all over ya.

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Sergei

Discussion Starter · #11 · Jan 9, 2014 (Edited)

SLSTech said:
4. uh no - why?

If there is a vapour barrier on the concrete then all water will be concentrated under it and can potentially damage concrete ... I think.

Have a look:
http://www.familyhandyman.com/basement/how-to-carpet-a-basement-floor/view-all
"Prevent damp basement floors from ruining carpet and other finished flooring. Install dimpled polyethylene to create an air space between the concrete and the finished floor, sealing off dampness and giving moisture a chance to dissipate."

Rest is clear enough

Thanks.

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Sergei

Discussion Starter · #12 · Jan 9, 2014

Patsfanindallas said:
I removed all the batt insulation on my pier and beam house because of the musty smell. Next week I'm having closed cell foam spray under the entire house. A vapor barrier was not recommended to me because it's closed cell foam.

Sounds good, but only if foam spray is used …
If it is a rigid foam panel …. Maybe be I need extra liner on top …

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Sergei

Discussion Starter · #13 · Jan 9, 2014

Ok
Current situation is clear – No need to seal the crawl space.
But …
Later on .. if they decide to add forced air heating and duct work In this space …
Just insulate duct and still do not seal the space?
{p.s} I am not sure about water pipes in the crawl space for now … Just insulate them better as well?

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Tom M

· #14 · Jan 9, 2014

They say that insulating the walls and rim joist with rigid insulation in conjuction with a mechanical dehumidfier. I have not done this yet myself. Since this is a retrofit and it might be a waste since the floor is uninsulated.

Personally I dont feel right about tight spaces, I like natural ventilation. But then that floor needs to be buttoned up well. Existing slab vapor barrier and size of the joist cavity would influence your insulating plan. SLStech is good with this stuff listen to him.

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