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Finishing crawl space

15K views 32 replies 5 participants last post by  Neofite 
#1 ·
Hi. My cape cod style house was built circa 1970. We have a crawl space that I'd like to finish as a play area for kids. I'm concerned, however, about air quality (e.g., asbestos, airborne fiberglass, etc). It appears to be fiberglass insulation - can I rule out asbestos? What's the best way to finish and seal the space? Right now there are bare joists on the floor with insulation in the spaces and nails sticking straight down through the roof into the ceiling. I was thinking of covering the floor joists with plywood base board, putting wallboard on the wall and canted ceiling, and then carpeting the floor. Any precautions I should observe? Any suggestions from folks who have done this already? Among other things, do I need to get my fiberglass insulation tested for asbestos? Thanks!
 
#2 ·
Hi. My cape cod style house was built circa 1970. We have a crawl space that I'd like to finish as a play area for kids. I'm concerned, however, about air quality (e.g., asbestos, airborne fiberglass, etc). It appears to be fiberglass insulation - can I rule out asbestos? What's the best way to finish and seal the space? Right now there are bare joists on the floor with insulation in the spaces and nails sticking straight down through the roof into the ceiling. I was thinking of covering the floor joists with plywood base board, putting wallboard on the wall and canted ceiling, and then carpeting the floor. Any precautions I should observe? Any suggestions from folks who have done this already? Among other things, do I need to get my fiberglass insulation tested for asbestos? Thanks!
This smacks of child abuse. Does your wife know you want to imprison the young'uns in the crawl space?
Ron
 
#4 ·
Seriously?



Disturbing thought!

Actually, the idea came when we were playing hide and seek and I used the attic crawl space to hide. Realizing that if it were cleaned up properly, it would be a fun "fort", I thought I would look into this. We have some friends who did something similar and their kids love it.
 
#6 ·
Dimensions



Me too!

I'll try to post a photo later today. It is about 60" tall. The floor, wall, and ceiling form a right triangle. So wall is 60" tall, floor is 60" wide, and ceiling is about 84" (from top of wall down to floor at 45 degree angle). The length of the crawlspace is about 8 feet. Even if we ended up using it for storage, it seems like a lot of space to not utilize in some way.
 
#9 ·
Jack, I'm probably not going to be around the computer much more today, or over the weekend, so if you don't mind, I'll also just plant a seed about air flow, particularly if he had planned to insulate between the rafters; not knowing all of the details, that sounds like it would likely present a problem. Then, the next thing would be the added weight of sheathing on the bottom of the rafters.
 
#14 ·
If that is the case then you should be good structurally, the next thing is, insulating the roof side if you are thinking of covering the rafters.

It looks as if you have this area open to the house already. Is it not cold where you are, that being said how hot will it get in the summer?
 
#16 ·
There is currently a small plywood access door that separates this area from the rest of the house. I would consider replacing that door with a small hung door of proper thickness and functionality.

If I insulate the roof and sides, do I run into any of the ventilation issues raised by Dexter?

Thanks.
 
#15 ·
Sorry; I didn't mean to confuse anything. Neo, it sounds like you may be describing an attic space behind a knee wall, possibly off of an upstairs bedroom? Assuming this is correct, I believe that there are a couple of other things that you need to consider. First of all is venting, and if you look down at the lower corner of your triangle, where the rafters set on the first floor walls, I believe that you can probably see light through you soffit vents. Air needs to be able to flow through these vents, up between your rafters, and out your roof vents. Maybe I am reading the situation wrong, but if this appears to be the case, you need to ensure that whatever you do does not impede this flow of air, i.e., you can't extend your flooring out too far, and you can't insulate between your rafters, without making other provisions for venting. Secondly, by attaching drywall, plywood, or whatever you decide to the bottom of your rafters, you are affecting your roof load. Sounds like a nice area, and I played in similar areas in my parents and grandparents homes, 50 some years ago, but some things to think about.
 
#18 ·
The answer is yes, Dexter brings to the table some very valid points on ventilation, if there is existing soffit vents, which there should be. This being said there must also be a ridge vent to allow the air out at the top, is this the case?

The easiest way to deal with those would be not to insulate the rafters at all, just cover them, yes it would make the area cold in the winter and hot in the summer, then you would insulate the access door to the area.

Really depends on how far you want to take this idea.

Mark
 
#20 ·
As long as you follow standard rafter insulation practices, you should be fine.
Heating and cooling will be an issue. Heat build up in that area will be substantial in the warm months. Sunny days figure 120 degrees F.
Ron
 
#21 · (Edited)
As long as you follow standard rafter insulation practices, you should be fine.
Heating and cooling will be an issue. Heat build up in that area will be substantial in the warm months. Sunny days figure 120 degrees F.
Ron
I am no expert, but I believe there will be a problem created if this advise is followed as there is already insulation and VB in the space (facing the conditioned side of the space below), if you add insulation and VB to the rafters with out consideration for this, you may cause or create a situation for condensation to form. Also if there are soffit vents they will need to be considered.

You could look at the rafters, are there any molded pieces coming up from the soffit through the insulation to allow air past the insulation?

Heres a good place to start for proper insulation ideas - http://www.buildingscience.com/documents/guides-and-manuals/irc-faqs/irc-faq-conditioned-attics

And yes regardless of insulation if there is no heat or AC ducted into the area the space will be uncomfortable.
 
#26 ·
If you do as Ron says, you'd also need to install rafter vents from the soffit up to the sloping part of the existing room (and beyond if they don't already have them). Then re-use the existing half wall and floor insulation (making sure the vapor barrier is removed too) to put between the rafters and the studs in the gables. I'd also apply 1" of rigid foam under the rafters and attach drywall directly to it. By the time you've laid a floor in this area you might want to decide if your kids will get enough enjoyment outof it and if you can use this as an adequate access storage area when they get tired/too old for it!
 
#32 · (Edited)
Neofite? Did you just convert? Proselyte?

You may have to look into the very corners of that attic space, where the roof meets the horizontal members. There should be soffit vents there, if not it would be wise, if you do nothing else it to add some venting to this space.

It will save your roof in the long run.
 
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