Closed Crawlspace | Finished TOUR
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- Опубліковано 25 лип 2024
- Check out a finished Addison Homes conditioned crawlspace!
#HealthyHighPerformanceHomes #DwellWell
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Man, would I’d love to have a crawl space like that. I’d put a tv down there 😂.
Thank you for the idea regarding the RADON vent. I am coverting a vented to conditioned crawl space, and adding such a vent is a great idea.
So glad you found that helpful!
Excellent demo and construction standards. Seen very few builders thinking on building science rather than on kitchen bathroom and living space aesthetics
Thanks so much! We agree!
the amount of work yall put into yall crawlspaces is amazing! You must be building million-dollar homes over there!
Thanks for the comments! Our average homes are in the $500k-$600k range after the price increases over the last two years, but crawlspace homes, as a general rule, are the most expensive due to all the requirements of an encapsulated crawl. We are constantly striving to reach lower price points so that we can provide high performance housing to as many people as possible, but there's always a balance between performance and affordability.
@@AddisonHomes that makes a lot of sense. I’m working towards getting my GC license so I can start building here in NC! Your videos are very inspiring!
After seeing the majority of homes here in Missouri being designed and constructed improperly, it's nice to see one that is built right.
Thanks so much!
I wish you were here in Houston, Texas. I need you ASAP ‼️
I'll help as much as I can! What's the need?
Well done video! One of the most important, yet most overlooked, requirement when conditioning a crawlspace is to ensure there is insulation on the exterior of the foundation and in particular the rim / edge joists. This is especially true if you are using batt insulation on the interior. I found this out the hard way as all my rim joist have suffered significant moisture damage. The theory is that when its cold outside the warm moist air of the crawlspace condenses on the rim joist. Then the batt insulation soaks up that water and exposes the rim joist to long term moisture. By placing insulation on the exterior foundation wall / rim joist you "warm it up" so that the interior side of the rim joist never reaches the dew point and moisture will not condense.
Thanks so much! Those are great points that are dead-on with a common source of condensation in crawlspace and basements for that matter!
Does this mean I cannot convert my vented crawlspace in to a conditioned crawlspace? unless I dig out all the dirt around the foundation and do insulation on the exterior as well? That is a bummer :(
@@sugumargovinda That's not true. I imagine the large reason for coating the exterior with tar is because allowing your foundation blocks to permeate condensation causes damage over time. So by sealing the exterior water that get's inside is raised through ground water, and that's what enters the interior perforated corrugated 4inch pipe.
You would still highly benefit from all procedures here aside from the exterior coating if you find the digging for it to be too costly or intrusive to plans you have (which could just be temporarily transplanted).
@@dominicstryfe7368 thank you so much
Excellent job. You cover many things most encap companies ignore. Question; What brand water sensor do you use? I'm retrofitting my own crawl space and will be doing something very similar with a floor drain at the lowest spot and would like to remotely monitor any water leak issues. Thanks.
Thanks very much! We continue to learn and improve our approach but want to share our learnings with others!
We were using the SantaFe Sentry sensor, but unfortunately, SantaFe no longer offers the product. We have found the leak smart system (leaksmart.com). In addition to wireless moisture and temperature sensors, the system can shutoff the home’s water supply in the event of a detected leak.
Thanks for the video. When you installed the polyiso foam board, did you apply adhesive or foam BETWEEN the pieces or simply butt them together and tape?
The foam panels are installed to the wall over the membrane with powder actuated fasteners. The joints are taped. Hope this makes sense!
Great videos on closed crawlspaces!! - thank you. You mentioned you are in a high termite area. Are the I-Joists treated? You mention in a later video that you use OSB on the walls. How does that perform with termites? We are in Hawaii and they want us to use Hi-Bor treated lumber, plywood and treated I-Joists.
Great question! We treat the wood in our construction with spray applied Borate 3' from any contact with Masonry. And, we must use pressure treated lumber in contact with masonry. Builders in our area can also use soil treatment or bait stations for termite control by code, but we prefer the spray applied borate.
Great video! One question. How does the supply air duct eliminate excess moisture in a crawl space? I understand the reasoning for not installing a return duct, but wouldn’t you still need something to remove moisture that will inevitably find it’s why in?
I assume, It would pump dry air into the crawlspace, and positively pressure the space. This would draw moisture out of the crawl space by increasing the moisture capacity of the air and pushing that moist air out of the crawlspace by the positive pressure.
We install a whole home dehumidification system which controls humidity in the main home and the crawlspace thorugh this supply air.
When you encap a crawl you do you use the white plastic on a concrete pad too. I built 10 yrs ago. Have a 4' crawl concrete floor cinderblock wall. Very dry no water problem but do feel cold and drafts in winter. Looking to foam board this spring but was thinking to do something on the floor too. Can I.
Just to make sure I understand completely, do you have a 4' tall crawlspace with a concrete slab floor? If so, did you install a vapor barrier beneath the slab? Where do you feel the cold drafts? Through the framed floor above the crawlspace? Is the crawlspace vented to the outside?
Depending on how cold it gets in your climate, the batt insulation can cause condensation on the rim joist in winter. Any batt insulation is vapor and air permeable, so you have equal dewpoint on either side of the insulation, but a much colder temperature at the wood. If the wood dips below the crawlspace dewpoint, it will get wet. The outside foam can help by raising the temperature, but it needs to be thick enough to always keep that rim joist will above the dewpoint.
Put another way: If you treat the crawlspace as conditioned, indoor space, it needs to have the same vapor control measures that rooms in the home would have. So if your climate requires a vapor retarder, you need either batt insulation with a continuous vapor retarder (extremely difficult to do properly in a crawlspace) or foam board.
And this kind of issue is exactly why I chose not to attempt a retrofit encapsulation on my home's crawlspace. The only material that makes sense, at least in a retrofit, is foam, and I've seen what ants can do to foam! I'll be going with an ATMOX system instead, basically treating the crawlspace as conditioned independently from the living space (using fans and dehumidifier) based on dew point.
Good points for colder climates. Here in climate zone 3, the exterior foam board insulation dramatically reduces the condensation potential on the interior of the rim and the R-19 I faced batt provides added R-value with the ability to dry easily to the inside. Dedicated whole house dehumidification including the conditioned crawl eliminates the condensation potential in the conditioned space. The unfazed batts further provide termite inspectability in this region with extreme levels of termites. Using spray foam on the rim joist area will give you a big exclusion on your termite bond!
You show a supply of conditioned air off of the main trunk. Is there a return? Or is a supply good enough?
Supply only is our approach which keeps the crawlspace under slight positive pressure and controls the humidity in the crawl. We follow the research based guidelines from Advanced Energy. We size the fresh air supply for 1 CFM of supply air for every 30 sq ft of crawlspace floor area.
I have a encapsulation in my crawl space and see that you put foam board against it? i was nervous to do that for fear of moisture forming between the foam and the liner? The liner was professionally done a number of years back before they insulated first. So now living here full time, used to be a summer home, I want to add more insulation to the foundation wall. Most of the wall is underground, so insulating from outside isn't a easy way to do this. Does gluing to the liner void the liner warranty or will the glue hurt the liner. I am also thinking maybe i can friction fit the foam between the joists and the ground liner? but worry that would shift too much with the groundwater moving the liner about. Appreciate any thoughts you might have. Thanks in advance.
A few questions regarding your encapsulated crawlspace:
- Where are you located?
- Do you have specific reasons that you fear moisture accumulation between the foam and liner? You mentioned groundwater.....
- Does your current liner extend up the interior foundation walls?
- Do you have any insulation on the interior of your foundation?
@@AddisonHomes Am in Central Ontario Canada, No particular reason other than liner to foam ? Yes i have a inside perimeter french drain on a liner covering the floor and walls up to the sill plate. There is no outside insulation. I did however place a radiant shield barrier just off the interior wall, this is hung from the joists and friction fit to the floor liner. There is 2 electric heaters on the north and south walls and the old vents have been covered up permanently. Thank you for getting back to me.
Also, I live in Zone 5 where there are fluctuations in temperatures seasonally. Would this system be a good idea for my crawl space? I have the same type of crawl space as was seen in the video which is a vented crawl space. I close the vents in late Fall and open them in mid to late Spring. The floor is covered with gravel.
This would be a great approach in any climate zone. The difference between zones is typically only the amount of insulation required on the foundation walls.
After installing something like this, how would one know if a foundation crack occurred? And if one did, would it matter if water were to penetrate through the foundation wall or no?
One wouldn't know if a foundation crack occurred unless it was visible above grade on the exterior - no different than with a basement foundation. If a foundation crack was significant, there could potentially be much larger problems of course. Water will flow to the path of least resistance - which is typically going to be down to the perimeter foundation drain and out to daylight. If it were to come in through a crack in the foundation, the membrane behind the foam board on the interior of the foundation wall should keep the water on the foundation side of the membrane - although this would not be desireable in any scenario.
I'm looking to buy a one way foundation drain like you install in your encapsulated crawl spaces. Do you happen to know where y'all get those or who makes them? Thanks
Search for Oatey #43904
Can radon diffuse through the encapsulating membrane?
Yes and No - not through the membrane necessarily but it could come in through an unsealed gap. We install passive and/or active Radon ventilation systems in every home which provides a path of least resistance for Radon gas to move from beneath the membrane up and out of the house. EPA has some good guides: www.epa.gov/radon/radon-resistant-construction-basics-and-techniques
Does the passive radon vent have a fan installed? Just wondering if it's necessary. I'd like to use one in my crawlspace.
Passive radon vents don't have a fan. They are just required to pass through a heated portion of the house before they exit. Active radon systems get a fan.
No fan, but we provision for a fan in the attic by supplying an electrical outlet and space in the pipe for an inline fan.
How did you frame the crawl access to disburse the weight since you cut out the joist?
We incorporate it into our floor system design with our engineer. It typically requires some engineered beams to transfer the loads to adjacent joists.
I may have missed it in this video or your prior videos but the membrane on the floor, is that just taped to the foam board for the seal? Thanks.
he membrane installed at rough in is installed behind the foam board and leaving a "tail" about 2 feet long at the bottom of the wall which is what the final membrane is sealed to after we startup the HVAC system.
@@AddisonHomes so the final membrane is taped to the sacrificial membrane at the wall/floor joint and that sacrificial membrane is what is taped to the wall behind the foam board.
I live in Chicago and we have a crawl space under the back of our home, I want to have concrete poured under there so I can use it there going to put stone in and cover it with 6 mil plastic. My question is do I need reed bar under here as well
No rebar needed unless you are adding some structural load onto the concrete. If only storage, none needed.
Thank you No structural load it's just an old crawlspace under a room addition off the back of our house@@AddisonHomes
Is insulation not necessary underneath the vapor barrier to reduce the thermal transfer of the cold ground into the conditioned space?
Not in our climate zone (3). We actually benefit from the constant ground temperature which helps offset the cooling demand in the home.
@Brian Critchlow I was wondering that very same thing. It's unfortunate that your question got no response.
Can a 2-3” concrete floor be poured over that existing system?
Yes it certainly can be.
You mentioned there is supply air in the crawlspace but where the does the air exit the crawlspace? Thank you.
This supply air makes its way back to the main house through leakage between the Crawlspace and the house - primarily at the Crawlspace hatch, which we install through the floor in the finished space vs an exterior Crawlspace door. Remember, this is a small amount of air - 1 cfm per 30 sq ft of Crawlspace floor area.
In some cases, we have placed dedicated returns in the Crawlspace, but in some versions of the building code, this makes the Crawlspace an HVAC “plenum” and adds additional challenges.
Checking the pressure difference between the Crawlspace and living area with a manometer is the best tool to determine the supply air design.
@@AddisonHomes Thank you for your response. I have a new construction with supply in the crawlspace and a vent that goes to my first floor. Even with the supply, the humidity level in the crawlspace seems high, hovering around 55~60% this past month and spiking to 70% periodically. I also noticed my radon levels are averaging 8pCi/L with a passive system like in the video. The quality of the sealing in the video is better than my build as far as I can tell. I thought of 2 ways to fix this. 1. Close off the supply and vent to the first floor and install a dehumidifer, that should solve both the humidity and radon issue. 2. Install a radon fan in the attic which should fix the radon issue and possibly help move more air through the crawlspace to reduce the humidity level? What is your suggestion for my situation and if you have any other ideas that would be great.
Could you list all of the products you use in this video?
We use many of the products manufactured by GMX (www.gmxco.com). We do not use their insulation product. We use foil faced 2" Polyiso foam board on the foundation walls.
So. How are those solar shingles in the neighborhood holding up?
They are doing great so far! We have added energy monitoring to our new homes which allows us and our clients to "see" how much energy the solar shingles are producing compared to the total energy use of the home. This has been a great tool to ensure everything is operating as designed!
@Chris Merck Great idea if we are near a stream!
@@AddisonHomes Except that in many places you create a liability if you obstruct a stream or creek, should it ever flood your neighbors up stream.
how much does it cost for about 500 square feet crawl space?
Hi - I think with something that small, there would be a minimum charge, but it would likely be in the range of $2,500 for new construction.
FUN FACT: The homeowners are now living in the crawl space, due to the fact that finances dried up prior to the living space actually being completed.
Ha! Fortunately, we've never had that happen, but it is costly to properly encapsulate a crawlspace and we often recommend walkout basements over crawlspaces when the topography makes sense. Much bigger bang for the buck with a conditioned basement and achieves the same objectives as an encapsulated crawl with a bonus - liveable space!!!
Do you only do conditioned crawl? I’m assuming it’s your standard base build option?
What if the home builder/buyer you are working with doesn’t see value? Then you are not their builder?
Todd, would you anything different in North West Arkansas, technically Zone 4! I’m building there and would like to communicate to my builder your best practice which is amazing to me.
I would follow the exact same approach in all climate zones with the exception of additional insulation on the perimeter foundation walls to meet or exceed the building code and omit the termite inspection gap at the top of the wall if termites are not present. Let us know if we can help by discussing with your builder if he would like some insights!
I know this video is old, and you might not see this, but I'm wondering if the barrier you are walking on is sitting on concrete, or is it just dirt?
Just raked dirt beneath the barrier.
What is under the crawlspace floor membrane? Is it gravel? If gravel, what size of gravel? Does this allow necessary air movement taken out by the vent system?
Just the dirt. If we cannot level the dirt due to rock or some other material, we "shoot' gravel fines into the space to level the subgrade. We put a tee on the radon vent system and extend each side with perforated pipe which allows for adequate airflow beneath the membrane.
How do you handle gas lines in closed crawlspace? What happens if there is a gas leak? is it OK to have a humidifier or forced ventilation in crawlspace when you have gas line running thru? Thanks.
The gas line should have no leaks regardless of whether a closed crawlspace or vented crawlspace! We test all of our gas lines for leaks anywhere in the home. Not sure what you mean by a humidifier or forced ventilation. We sometimes install DEhumidifiers and supply the crawlspace with air from the HVAC system. Hope this helps! Let us know if not.
@@AddisonHomes I think what is being asked is about sealing the gas line under the crawl space.
If so, the rules say you can't seal BOTH ends of the pipe but most leave one side open to air flow. If you running UNDER the wrap, then it needs to in a PVC pipe that is open at one side (so I'm told). Since the crawl space is vented to the interior of the house (as opposed to the outside), then code should see at no different then an exposed pipe running thru the living space.
Commenting from the state of Maine: with all that goes into conditioning this crawlspace, why not just put in a full foundation? Crawlspaces already require concrete forms, so for the cost of the additional concrete and the addition of a bulkhead exit you gain an entire extra floor. Just curious to hear your thinking. p.s. love the videos!
I agree that there are many steps to install a conditioned crawlspace correctly! In fact, it is arguably the most expensive foundation type for most homes. In Maine, it definitely would make sense to build a full basement foundation, primarily due to the frost line depth - from a quick search of the frost line depth in Maine, it looks like it is about 5-6 feet deep in southern Maine. Since we have to install foundations below the local frost line, you would have to go down at least 5-6 feet for your foundation in Maine - so you might as well go 2-3 more feet and make it a basement! In South Carolina, our frost line is a mere 12 inches deep!!! So, we aren't required to go so deep, and, we typically install crawlspace foundations using CMU masonry block, not formed concrete. Our crawlspace foundation walls are typically only 4 feet tall, and formed concrete for these short walls are typically more expensive.
I frequently suggest that clients consider basement foundations instead of crawlspace foundations if the site topography is conducive. The South Carolina market typically builds "walk out" basements, so if the site has 8-10 feet of elevation change, the basement foundation is a no-brainer! Basements have all the benefits of encapsulated crawlspaces, with far greater value and usability!
So glad you're enjoying the videos!!! Hope you share them!
@@AddisonHomes Thanks for the reply Todd! Crawlspace logic makes much more sense to me now, thanks for sharing the pros and cons. Keep up the great work!
@@SquishyMit You're very welcome! So glad it makes sense! Spread the knowledge!
Where can I buy the foundation drain? Could you please provide the link
www.gmxco.com/products/waterproofing-systems.html
Nice video but why not just eliminate the crawlspace and all the costs associated with it and use a slab foundation. The duct-work could be completely eliminated using a non duct system. Additionally the drain system for the crawlspace, as depicted, is an entry way for mice.
His Steve - check out the previous comment and response to the same question from Steve Mitman.
To answer some of your specific questions:
1) Slab foundations are less expensive and we definitely recommend them or basements instead of conditioned crawlspace when the topography is conducive. Unfortunately, there are situations where the slab can be more expensive due to the sloping topography of our area and basements are more expensive than the crawlspace although they are greater value.
2) We try to eliminate ductwork where possible, but the ductless systems aren't always a fit. To condition small bedrooms, for example, even the smallest ductless head might be oversized - we then have to resort to ductwork. We also have to address ventilation and fresh air into the home, which typically requires ductwork to reach the bedrooms to maintain indoor air quality.
3) In 20 years of building, I've never had mice come into a house through the foundation drain. The one way backflow valve prevents this as and entry point.
Thanks for the comments!
@@AddisonHomes Thanks for your response. Many do not do so.
@@AddisonHomes So does that mean a stem wall slab is more money than a encapsulated crawl?
@@garrettp.5018 in some environments, yes
I thought all craw space is as low as 18inch high like mine
We try to avoid this on our crawlspace. Our spec is a minimum of 4 ft. tall foundation walls. Its a bit more expensive, but saves massive headaches for plumbing, ductwork, and future access!
Just bought a house and going from 6-12" in one half and 30" on the other to a 10'and 5' crawl space. I dont what to do with myself I'm so excited. Want to make it usable and add a ladder hatch
@@nateb4543 That sounds like a dream!!!!
@@AddisonHomes best part was that we made an offer and disnt even see the crawlspace. Found it during inspection. I'm floating