\u00a9 2022 wikiHow, Inc. All rights reserved. We have since determined that there was quite a bit of mold growing under the house and the contractor simply encapsulated the crawl space without notifying us of the mold issue and without removing the old, moldy fiberglass insulation. Thank you for your response. basement act the same as the can. The house is located in East Tenneessee.

The more research I do, the more Im finding that its better to seal both foundation vents and encapsulate my CS. Chlorine is a powerful whitener and disinfectant, but Tim, Were told itll do the trick by keeping moisture below, which well reduce/eliminate by installing a sump pump and dehumidifier in the basement. But many say plug off all the vents to the crawl space and make it air tight no fresh air ventingis that really what I want to do???? The crawlspace is earth and the floor is between 2 and 4 above grade. Youll also need to permanently seal & insulate the CS vents. You can run the rigid foam right over the vent openings so that theyre sealed off as well. When theres a really heavy rain the water has come close to the floor. Tip: If you plan on storing items in your crawl space, get 12-mil polyethylene sheets so they dont rip or tear when you walk on them. We have been having an ongoing problem with voles burrowing into the crawlspace as well as squirrels.

Could I just put the same foil faced insulation on the floor of the crawl spaces and foam the joints where the floor meets the wall? Termites and carpenter ants are unlikely to go after wood that stays dry, so your risk is minimal if you can keep the rim joist area dry. I have a unique situation with the design of of my crawlspace. Id recommend fully encapsulating your crawl space. I have a 1925 log house in Finland (http://villainkeri.com/wp-content/uploads/2014/01/Winter.jpg) that has an earth floor underneath. Hi Tim If the floor for your crawl space is uneven, take the height measurement in multiple spots on the wall and use the tallest height you find. I hope this helps. How many Hilti plastic fasteners do you recommend installing in a 4 x 8 sheet of foam insulation to the block wall BEFORE the vapor barrier is installed? Can I obtain an R-19 with 2-3 of rigid foam and 12 air space?

I live in a house built in the late 1930s. Since adhesives can fail over time, we recommend screws or nails. I just found a large number of them behind a piece of rigid foam insulation that we glued against the concrete block foundation to insulate the walls. Its fine to use the crawl space floor for storage, but (as you point out) care must be taken not to tear or perforate the floor vapor barrier. After growing up in construction and with more than 30 years in the field, she believes a girl can swing a hammer with the best of them.

They also put a new vapor barrier down. Dont install insulation while theres still moisture in your crawl space since it could easily develop mold. I have seen conflicting things on this. of foil-faced polyiso board (youll probably have to buy thinner polyiso board and install a couple of layers.). Immediately position the matching piece of plastic sheeting over the wall, ensuring it is higher than the wall, trailing over the floor, and extending on to the walls on either end. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. You dont need heavy equipment to excavate a giant hole for a full basement. If your crawl space is closed or encapsulated there are several ways to insulate.

However, its important to seal the ductwork.

4. Instead of encapsulating the crawl space, it would be better to install flood vents in the CS vent openings, so that flood water can flow through the foundation rather than beat against it. Tim, Kathy again. Closed crawl spaces keep cold and hot air out. My heating pipes run through the crawl space. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. Exterminator (O.) Great information on here. Should I tape the seams of each layer of the rigid insulation? If youre going to insulate the walls, install the rigid foam after air-sealing & insulating the rim joist. Tim, I have been reading that when using foamboard in your rim joists or basement walls, you need to afterward cover the board with fireproof drywall. The basement guy stated that he would dig a trench but not re-cover with cement?

it appears some installers are placing the plastic on the wall before placing the foam board? The joist spaces are open. Required fields are marked *, Designed by Elegant Themes | Powered by WordPress.

Cottage is located on Lake Huron. Thanks. Spray Foam Insulation How deep should wall extend below grade to deter critters? For some reason, the builders added crawl space vents.

This will hopefully prevent any standing water. Third, I suggest you consider either replacing old basement windows or simply cover them with insulated, airtight covers. The addition is recent and is framed in the platform fashion with a rim joist which is supported by the short stud wall which rests on the concrete foundation. Your query leaves out some important details. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. I have a unique situation in that I have a home with radiant floor heat via pex tubing and aluminum fins running through the joists about an inch from the subfloor. Get it dry, so youre creating a mold-hostile environment. The whole area will be fogged with an anti-microbial solution.

If the fiberglass insulation you installed is OK, its fine to leave these batts in place. Thanks Timso the plan is..3 rigid foam sheeting between the floor joists..1 foil backed rigid foam for the foundation walls.and 6 mil plastic sheeting on the floor.

They are both dry and over the last year and a half have had no signs of water in them.

After the concrete floor has hardened, you can trim off the excess plastic. Leave the vents open? Once the crawl space is encapsulated, it will be within your homes building envelope, so the interior door should still be fine. No heat, no insulation and no laundry room! there is a regular interior door that accesses a closet that is open to the crawl space. But when it comes time to sell your house, the WaterGuard concealed perimeter drains and nice-looking sump pump system will impress prospective buyers instead of scare them like open trenches will. Scott: If you want to keep using the crawl space ceiling as your thermal & pressure barrier, keep the fiberglass insulation in place. Well address this issue in more detail in a future blog, but for now heres the short answer. Then install unfaced fiberglass insulation to the full depth of the joists. SPF is more expensive, but its very effective insulation (R-6 or more per in.) Foundation walls are 3 feet or less. I had a company come in to get an estimate on encapsulating, which consisted of the following: My problem is the floor is typically 50 degrees and room is 68 and our energy consumption keeps creeping up despite the outside temperature being constant (around 6 degrees). Michael Church has been involved with indoor air quality since 2005 and feels the unhealthy crawl space is one of the major problems causing poor indoor air quality. The crawlspace is vented, I left out that detail, the denim batts I am considering were decided upon because there is no fiberglass to contend with and their recycled nature, the are actually made of recycled denim jeans and jackets, etc. mold infected portions of your home, or contents, and take them to a Best Way to Insulate Closed Crawl Space The extruded polystyrene panels are a bit less expensive than the polyiso, and no less waterproof. We dont want to reclaim the basement for living space, but do want to keep it and the crawlspaces as dry and mold-free as possible, and we want to prevent mold and other bad stuff from coming into the house through the chimney effect. Your thoughts? There is a radon mitigation system with pipes coming from the main section of the basement as well as each crawl space. But keep in mind it will flood. Always wear safety glasses, a dust mask, and gloves while working with foam insulation to prevent any irritation. Read more The room above has radiant heat panels on top of the subfloor, only penetrations are for pex tubing and wiring. Once this happens, youve got a controlled environment where mold cant grow, and a crawl space thats more of an asset to your house than a liability. Hi Janis, Some of it will probably have to come out anyway to facilitate the new ductwork installation; the rest is often a favorite habitat for mice. Tim In need of crawl space advise. First, there is a porch on the front and side of the house that is open to the CS. Leaky ducts can diminish HVAC efficiency by 20%. The walls have poorly applied 1/2 inch rigid Styrofoam, attached to the concrete with fasteners. I have been reading through the posts as well as other websites and am getting mixed messages. If it isnt, Id opt for encapsulation with moisture control as mentioned. If budget is a concern, you might consider spending the insulation money on rigid foam for the basement walls instead of for the CS floors. There is a thin layer of foil reflecting insulation under that followed by R-30 unfaced and string tied to complete the insulation. Lowering the humidity of the space (and drying out the wood) is the only way to avoid additional mold problems. Yes, youve been lucky. The house is brick and around the exterior walls (brick) there are block support piers about every 8 foot, so they stick out either 6 or 8 from the brick. Pick the crawl space opening that would be most suitable for access. We live in TN and recently purchased an old farmhouse built in 1902. Also, would I use spray foam at the top of the foam board where it meets the sill plate in order to seal it? Good luck. Adhere the plastic to the next, and each remaining wall, following the same procedures. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. He was also going to put a proper sealed top on my sump. ft. 9 ft. ceilings. I have some follow-up questions.

Two access doors made of barn boards. The rigid foam application (to the bottom of the crawl space joists) should protect water lines that run in the joist space. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. Read more A good first step would be simply to insulate the rim joist by friction-fitting rigid foam insulation against the rim joist and between floor joists and then sealing around the foam board with 1-part spray foam. Hi Tim, great website. thick) along the bottom edges of the joists, using screws and large washers. After the storm, we had the insulation removed by a contractor and he re-insulated the crawlspace with fiberglass batts (that were installed with the vapor barrier down) and then attached 1 Tuff R foam board to the joist, but it was not taped and sealed as you had mentioned. Because youre working in a space thats dark, cramped, dirty and damp, its hard work. Instead, dig around the pipes below the entry door, encase the pipes in tightly packed sand, and then lay down a layer of brick to form the bottom of the doorway. Karl: The crawl space is vented and not insulated. The best way to insulate your crawl space and the rest of your home is a combination of air sealing and thermal breaks. This means that you don't have to cover it with a fire-retardant material such as drywall. I have a crawl space and my feet get cold in the winter. I have a home in Ocean City NJ that has a crawl space with vents. Now worth at best $11-15. Or is it smart spending the extra money for the ridged foam board insulation? Is there a downside to such actions? If your crawl space already has moldy, damp wood, youll need to run a dehumidifier after sealing the space to dry out the space. 5. I have a cottage on piers which had a incorrectly insulated crawl space. Sealing the seams between panels with tape will improve the air barrier. Are you looking to air seal or create a thermal break or both? The crawlspace is vented, and fiberglass batting was installed between the floor joists a few years ago. (overkill, but the Mrs. doesnt like to be cold). My guess no wall insulation, unless it was installed more recently. Insulate and air-seal as much of the rim joist (mudsill) area as possible. Id frame & finish an access door with beefy stop molding that would accept equally beefy weatherstripping for maintaining a good airseal. 3) The flex ductwork needs repair or replacing due to critters. A bit of information, then questions. Tim I have a complicated problem. So yes, I would run a dehumidifier in your crawl space until you get below 50% humidity, if possible. (The basement and the crawl spaces are connected via a porthole-like vent.). Thank you again for your advice. Do you know where I can get it? The contractor also sealed six of the eight C.S. I would definitely remove the old fiberglass insulation. This stippled plastic sheet material is available from most Basement Systems contractors. Sounds like youve got a classic vented crawl space that needs to be encapsulated. By allowing flood water to flow through the foundation instead of driving against it, theres less chance of severe destruction. Multiply the results for each wall to determine the square footage. Make sure to air-seal the penetrations where duct boots go up through the floor, and seal the new ductwork so that you dont have crawl space air being pulled up into the house. My house is a ranch with a basement that is half finished and half crawl space. ET: Instead of building a cinder block wall to separate the porch from the crawl space, you could frame a partition wall with 24 pressure-treated lumber, then cover this framing with a thick poly vapor barrier.

Thank you for responding lightening fast! He said he gladly would if I wanted to but does not see the need for it. Im very much in the same boat as Kathy from Savannah. Its not my intention to use nails or fasteners unless I have to. Thanks so much for the advice. We have a similar setup (townhouse in flood plain, on foundation and cement piers, crawlspace under main floor, venting to allow air/water movement between adjacent units) . This strategy will cost much less than retrofitting solid walls beneath your house, and it will result in major comfort and energy improvements. This can be achieved with a couple of inches of foam between joists, and a continuous layer of foil-faced polyiso board secured to joist bottom edges (seal the joints with aluminum tape). Which moisture barrier do you recommend on the concrete floor/walls? The joists are nailed to the sides of the studs 3 ft. above the top of foundation, and there is a ledger board underneath supporting the joists. Installing a thick poly vapor barrier over the floor and up the walls should go a long way toward reducing radon levels, but have the test done anyway. The outside walls (and some inside walls) are cinder block up to the roof. The same company also said that I could get by with simply installing a 12 mil. I usually recommend that any fuel-burning appliance in a crawl space be a sealed-combustion unit that relies on PVC pipes to provide combustion air and vent combustion gasses. Drafty homes are homes with little to no air sealing. There are signs of mold on the floor joists. Make sure that the panel adhesive is compatible with the foam board. Even so, there is the mold. Start out by air-sealing and insulating the rim joist.

Flood vents can mean lower flood insurance too, so theyre worth checking out. I have a question, hopeful to get some feed back. When I removed the fiberglass batts it was because they were looking like drunken stalactites and plastic on the floor has water droplets beaded up on top. Hope all that makes sense, thank you in advance! 40 year-old house is in Pacific Northwest, close to ocean, on well-drained sandy soil. Youll have ongoing moisture problems. The VB should lap up onto your walls. Good luck. We try to stay clear of covering the entire sub-floor with insulation because we are typically closing crawl spaces. The foamboard on the link is the only type we use and recommend. By your description Im going to guess that the window openings are small and your basement wont need natural light if its not going to be used frequently. My situation is a combination of many others discussed earlier. I was wanting to know your situation; many of us have created some nice procedures and we are looking to If I understand your advice correctlyyou are saying first use a 1 part spray foam Great Stuff (is this specifically called 1 part?) You are correct in that a rigid style foam insulation is the best form of insulation to use when trying to seal your crawl spaces, as long as each panel is correctly taped together this can be one of the best ways to essentially vapor lock your crawl space, it stops air, moisture, dust, smells, and is truly a great way to eliminate the above from your home, the johns manville foil board is also a good product to use for this. The CS has a concrete floor with a foundation vent on each side of the house. We have a proposal to encapsulate as you have described. Its also smart to remove sharp rocks from a dirt crawl space floor before laying down the vapor barrier. If you cant source washers, its possible to make your own from 2-in. We have recently noticed a musty smell in the master bath. I want to condition both these rooms for the sake of cold air coming through our upstairs floors. Is it still necessary to install a vapor barrier on the dirt floor? It will re-use all the Tuff R on the walls (after disinfecting them for safety). Similar to mudding drywall in order to prevent moisture from escaping from between the panels. If you seal and tape the joints between foil-faced insulation board, no plastic vapor barrier will be necessary.

We recommend foundation wall insulation as recommended by the Department of Energy. Is there an issue if spray foam under concrete with pipes going through it gets soaked in a flood?

Theres a small sump pump, but I dont think there is any perimeter drainage. Up north where frozen pipes are an issue every winter, beach houses built on piers and crawl space houses have a way to protect water lines that extend beneath the house. Alternatively, you could friction-fit rigid foam insulation between the joists and fill gaps with one-part foam (GREAT STUFF). There is no access to the foil/shiny type of insulation that seems to be what most people are using. I have already scheduled a termite inspection and plan on tackling the rest within the next two weeks. I have asked around the area and most insulation installers do not recommend having the plastic secure the insulation.