Crawlspace insulation - be conscientious to get it right

A crawlspace comes with all the downsides of a basement, merely it is just too depression a infinite to be functional either across the folded plastic christmas tree and a couple of boxes of baubles. Unless in that location is a skilful reason for it, going through the process of pouring a footing, then a physical wall, then building a subfloor above and only exist able to access information technology on your hands and knees is a lot of effort for the value y'all volition get from that space. If you don't want a full basement, a smashing alternative is to build a slab-on-form.

Important note: The following crawlspace solutions are recommendations for how to deal with moisture and rut loss merely, and provide simply an anecdotal overview of how to bargain with radon gas. We would recommend having your air tested for radon, and if it is above Wellness Canada's recommended rubber levels (200 Bq/thousand³), please run across our pages on radon gas mitigation in crawlspaces .

Fixing a clay floor crawlspace:

All too often a crawlspace volition accept aught but a clay floor, and probably some un-insulated walls. The result of that is an unending source of humidity every bit wet in the footing evaporates into the air and can condense on cold walls and joists where mold can establish itself.

That dank air will inevitably exist circulated throughout your dwelling, providing humidity, mold spores and a pretty nasty smell that will be the dominating odour of your domicile, furnishings, and your wearing apparel, and so yous will take that aroma everywhere y'all go. Rotten huh?

Crawlspace vapour barrier © Pescrawlspaces.com

For those with nothing simply a dirt floor, the single about important thing to do will not price much - cut off the moisture supply to the air past laying down polyethylene directly on the ground. The standard half dozen mil poly vapour barrier will work fine as a DIY solution. Practice the best job yous can and seal the joints, merely remember - if you did nothing else across laying it down over most of the floor, even without taping or sealing it, you would reduce the amount of moisture in the air. If your crawlspace admission is inconsistent and you can but promise to do 80% of it, do it anyway; you will notice a very big deviation.

The 6 mil poly is far from beingness a complete crawlspace solution, just we're putting that out at that place so as not to leave those with really tricky crawlspaces or tight budgets feeling down-hearted. This is not an 'all or nothing' state of affairs where there is no bespeak doing anything if you tin can't practise it all - do as much as you tin can, it will help.

Insulating crawlspaces:

The best way to insulate a crawlspace would be to do it from the footing upward and consider information technology just part of the conditioned infinite equally you would with whatever basement. We make no secret of the fact that nosotros aren't huge fans of spray foam due to the emissions associated with information technology (with exceptions for eco-friendly spray foams) merely this is ane identify where it tin can brand a lot of sense.

Spray foam is done apace, it has a loftier R-value, provides an air and moisture seal and fills all the tiny holes. This is not a DIY job so information technology will be amid the more expensive options, but information technology will work well, and best of all ... someone else will be slithering around in your crawlspace rather than you. Since information technology volition act every bit a vapour barrier, there is no demand to lay downwardly poly ahead of fourth dimension; information technology can become right confronting the dirt.

When it comes to insulating the walls, there are a couple of ways to get about this – Building Lawmaking requires whatsoever crawlspace more than 5 feet high to take burn protection covering any foam products, in which case you tin can frame a 2x4 or 2x6 wall 1 inch abroad from the physical wall; sitting information technology on minor chunks of cream will keep it from existence in contact with the ground and absorbing wet. Spray foam is then applied to the walls behind the studs and into the cavities, you tin go out enough room to practice whatsoever wiring if required.

Spray foam insulating basement walls © Bala Structures

The foam needs to so exist covered with drywall as fire protection, which tin be attached to the stud wall. No vapour bulwark is required in add-on to spray foam. Building codes alter and can vary by region, then ostend this locally, only currently The National Building Code in Canada for example allows foam insulation without burn down protection on crawlspace walls that are less than v feet in height.

An additional choice, for walls merely, that you can do yourself is to apply EPS foam boards directly to the concrete using either strapping and tap con screws, or an advisable adhesive that is suitable for foam boards (it should say then on the tube). EPS tin be substituted with XPS cream, simply given its much higher greenhouse gas emissions, we adopt to recommend EPS. XPS qualifies as a vapour barrier at i inch, and testing shows that EPS foam acts equally a vapour bulwark (one perm) at 2 inches or thicker.

Rock wool insulation batts on basement walls © Ecohome

Rock wool (mineral wool) boards are an alternative product yous can employ and they are made from recycled stone dust, so it does not burn and does not demand to be covered for fire protection. But mineral wool is not a vapour barrier, so it is best to utilize a poly membrane against the concrete beginning.

Notation: Taped XPS foam is an air bulwark, but EPS and mineral wool are not. Air doesn't leak through intact physical but it is quite likely that crawlspace walls will leak air. If you accept a stone foundation, sometime cracked concrete or cinderblocks, bringing the poly bulwark up the wall and sealing it to the rim joists will provide y'all with an air bulwark.

Preparing a crawlspace for vapour barriers and insulation:

Outset articulate the space every bit much every bit possible then you have room to motion around. Ensure in that location won't be any problems with bulk water aggregating by installing a sump pump at the everyman indicate. Even if you've never had flooding in the past, that does not mean you volition never take it in the futurity. We've never heard anyone say they regretted installing a sump pump.

Remove any sharp rocks and obvious obtrusions for a more even surface so that you won't tear the plastic as you walk on it.

Should you vent a crawlspace?

No, you should not. Drawing humid air into a cold crawlspace in summer or winter defeats the purpose of stopping the source of wet. A wet protected crawlspace will probably exist quite cool in summertime and should be less humid than outdoor air, and so moisture tin can condense on the cold surfaces of wood and physical. Information technology'south meliorate kept sealed up once you accept dealt with moisture and air quality issues. Be sure to monitor the humidity levels one time work is completed, you lot will likely need to include a dehumidifier to continue humidity down.

When shopping for a dehumidifier make certain it can be operated continuously with a drain hose, don't go 1 that needs to be manually emptied. They tin hands fill up at to the lowest degree once in a 24-hour interval, and if you're not there to empty it regularly it will stop working.

The volume of water that will be produced past a dehumidifier is not so great in quantity that it necessarily needs to be directed to a drain, which likely won't even exist in a crawlspace. You can have it set it up to bleed right into a small pit in the dirt below the membrane and it will absorb back into the ground.

Removing radon gas from crawlspaces

We highly recommend getting your air tested for radon gas before offset work to determine if whatever measures will exist needed to protect your air quality. Air contaminated with radon gas is a serious health gamble and is the second leading crusade of lung cancer after smoking. Please see our folio on crawlspace radon mitigation for more data.