How do ICF builders handle door threshold conditions? Do they extend the floor slab over the top of the ICF at the door opening and if so, do they typically extend it to the outside face of the underlying concrete core or beyond to the outside face of the EPS?

on mine I set the top of the basement ICF at the top of the floor structure. The floor sheathing sat above this. I then flashed and set the door. I will pour about 3/4" of self leveling compound in the space between the subfloor and the door sill. this, in my view, allowed for a better air seal and keeping possible moisture below the floor line and away from the wood subfloor. Have done plenty of remodels where this is rotted out under the door.

Posted By Lbear on 06 Mar 2013 12:38 AM
How do ICF builders handle door threshold conditions? Do they extend the floor slab over the top of the ICF at the door opening and if so, do they typically extend it to the outside face of the underlying concrete core or beyond to the outside face of the EPS?

Lbear - at least leave the outside panel of the icf to the top of the floor. I prefer to depress the concrete core 2" and insert a piece of 2" foam under the threshold between the two panels to totally encapsulate the concrete core. The exact detail varies with the type of flooring you are going to use. There are some commercial gaskets for under the threshold or you might use a large bead of silicone or urathane.

Posted By FBBP on 08 Mar 2013 01:25 PM

Posted By Lbear on 06 Mar 2013 12:38 AM
How do ICF builders handle door threshold conditions? Do they extend the floor slab over the top of the ICF at the door opening and if so, do they typically extend it to the outside face of the underlying concrete core or beyond to the outside face of the EPS?

Lbear - at least leave the outside panel of the icf to the top of the floor. I prefer to depress the concrete core 2" and insert a piece of 2" foam under the threshold between the two panels to totally encapsulate the concrete core. The exact detail varies with the type of flooring you are going to use. There are some commercial gaskets for under the threshold or you might use a large bead of silicone or urathane.

Any photos or details?

Lbear - I don't usually have luck uploading images but we will try this. If it doesn't show, tell me the simplest way to do it and I'll try again. Door_threshold.pdf

Posted By FBBP on 08 Mar 2013 08:12 PM
Lbear - I don't usually have luck uploading images but we will try this. If it doesn't show, tell me the simplest way to do it and I'll try again. Door_threshold.pdf

It worked, thanks!

Posted By Lbear on 06 Mar 2013 12:38 AM
How do ICF builders handle door threshold conditions? Do they extend the floor slab over the top of the ICF at the door opening and if so, do they typically extend it to the outside face of the underlying concrete core or beyond to the outside face of the EPS?

I formed my sills with concrete. Stone would have been nice, but pretty pricey. I planned to coat the concrete with a texture concrete coating but the lumber yard I was going to buy it from closed down and now I don't remember the name of the stuff. Here's some pics of how I did it.




This is the garage man door formed. The outer part of the sill extends beyond the foam and down about 2" to ensure water runs down to the outside of the wall. You can see the blue foam strip for a thermal break between the sill and floor slab.




Here's the finished product. The garage floor is about 1" below the sill elevation so the concrete slopes up to sill height. The threshold in the door frame has a thermal break built in and covers the thermal breaks in all the doorways.




This is the front door sill. Its top is about 1/4" higher than the stack up of the tile backer and tile. You can't really see it but the sill slopes about 1/2". If I ever get it coated it should look pretty decent, I think, and for a lot less than a stone threshold would have been. The black felt was a failed attempt to keep the subfloor clean and dry during construction!




This is the patio door sill formed. There is a wood strip below the 2 x 4 along the edge of the subfloor about 1/2 the width of the inner foam. After the concrete set that strip was removed and the gap foamed in. The door threshold covers the foam thermal break. Tile coming up to the door was angled up about 1/4". The outdoor slabs are about 3/4" below the finished floor and 1" below the threshold. I used ADA thresholds.




Here you can see the height difference between the subfloor and sill. The thermal breaks work great. The floor is only a little bit cooler at the door than at the interior of the house with an outdoor temp of 10°F and colder! And I think that was from air leakage under the door. Absolute tightness isn't possible with an ADA sill. I have no steps in the house, or outside. It's all wheel chair and walker friendly. If the house you're building is your planned last stop between now and when you're 6' under, you might take things like walkers, arthritic hands, weak arms, etc., into consideration in your design. Make your stairway wide enough to accommodate a stair lifter some day, and your hallways wide enough to maneuver a wheel chair down them. All my doors, except for the toilet in the corner of the garage, are 3' wide. I even put electrical boxes above the exterior doors for possible future electric door openers. Almost nothing in the house, including the exterior door locks, requires a twist of the wrist.

Now, all of this probably isn't the normal way builders do things, but since I'm not an experienced builder I wasn't constrained by a builder's paradigm! As you've probably figured out, it's kind of surprising how something like a simple door sill, ain't always so simple when you start taking thermal issues into consideration.

Thanks for the photos and info!

Does the foam have to be the heavier duty 2LB foam or XPS?

Looks real nice but I'm concerned with the concrete sill tied to the concrete core. Given the conductivity of concrete, a lot of the btu's trapped in the core are going to use the sill as a radiant panel to escape. So in reality the outside foam can't contribute to the overall R value of the wall. Just my thinking ;-)

Posted By FBBP on 08 Mar 2013 08:12 PM
Lbear - I don't usually have luck uploading images but we will try this. If it doesn't show, tell me the simplest way to do it and I'll try again. Door_threshold.pdf

It shows the interior concrete slab at 1.5" thick. Am I reading the detail wrong?

Posted By FBBP on 09 Mar 2013 02:43 PM
Looks real nice but I'm concerned with the concrete sill tied to the concrete core. Given the conductivity of concrete, a lot of the btu's trapped in the core are going to use the sill as a radiant panel to escape. So in reality the outside foam can't contribute to the overall R value of the wall. Just my thinking ;-)

I'd be inclined to say valid point, but.... Like I always told my kids, "You can't have everything!" I'm not sure how much I thought about that issue during the design phase. As far as thermal considerations my top priority was to make sure the sill was decoupled from the house interior. Cold floors next to the door in winter are not pleasant!

It's probable there is heat lost through the sill, but it would be mostly by conductance to the slab outside, not radiation. But without doing a complicated heat transfer analysis, which I'm not able to do since I don't have a $10,000 heat transfer computer program and mini main frame to run it on (!!!!), I really doubt the quantity of heat lost is significant in the total scheme of things. In that regard though, I really should have put a black board filler, or foam, between the sill and the slab. That aspect completely escaped my analysis. But there is a lot of heat stored inside the mass of the wall around and below the doors so I doubt the temp of that concrete drops noticeably.

Maybe Dana will offer up a more informed comment.

Posted By Lbear on 09 Mar 2013 04:00 AM
Thanks for the photos and info!

Does the foam have to be the heavier duty 2LB foam or XPS?

It's Dow blue board, which I used for of that type of insulation purposes. I didn't use it so much due to its higher R value but simply because of its structural strength for cutting and handling. Keep in mind there is an issue of diminishing returns when trying to chase down every last lost Btu but in the process expending a lot time and effort, let alone money.

FBBP's sketch looks like a good way to go, particularly if you use a pre-built door frame with a large sill attached. If you use a stone sill then you need to be sure to get it anchored securely to the concrete in the wall. Bolts through the stone under the door frame sill would work. The main downside that came to mind first thing when I looked at the sketch, is you have to make sure the concrete is finished smooth and at the right elevation below the doorway.
 

Posted By Lbear on 09 Mar 2013 04:31 PM

Posted By FBBP on 08 Mar 2013 08:12 PM
Lbear - I don't usually have luck uploading images but we will try this. If it doesn't show, tell me the simplest way to do it and I'll try again. Door_threshold.pdf

It shows the interior concrete slab at 1.5" thick. Am I reading the detail wrong?

No your not reading it wrong. This is for a hot water floor slab that is supported by a standard wood floor system.





If you wanted to put the door on just the floor sheathing it might look like this. door_sill_on_sheathing.pdf


And if you want to put it on a slab it might look like this.door_sill_on_slab.pdf

Posted By dmaceld on 09 Mar 2013 07:37 PM

I'd be inclined to say valid point, but.... Like I always told my kids, "You can't have everything!" I'm not sure how much I thought about that issue during the design phase. As far as thermal considerations my top priority was to make sure the sill was decoupled from the house interior. Cold floors next to the door in winter are not pleasant!

It's probable there is heat lost through the sill, but it would be mostly by conductance to the slab outside, not radiation. But without doing a complicated heat transfer analysis, which I'm not able to do since I don't have a $10,000 heat transfer computer program and mini main frame to run it on (!!!!), I really doubt the quantity of heat lost is significant in the total scheme of things. In that regard though, I really should have put a black board filler, or foam, between the sill and the slab. That aspect completely escaped my analysis. But there is a lot of heat stored inside the mass of the wall around and below the doors so I doubt the temp of that concrete drops noticeably.

Maybe Dana will offer up a more informed comment.

dmaceld - you are probably right about it not being a biggy. Please consider that I am use to using minus 32 C as my design temperature. My thinking over the last few years is that north of 49 the concrete core in an ICF should be totally encapsulated in foam, including door and window bucks. This allows for the concrete mass to use its specific heat capabilities without worrying about the conductance. I believe that as your design temperature rises this becomes less important. As you slide into a cooling dominated climate, the protected mass actually becomes a negative in some situations. That just a gut feel as I have not had to worry about 105ºf and 95% r.h. in many decades ;-) but naked mass will definitely have more impact on temperature swings.

My doors are going to be inset, since putting the frame flush with the outside wouldn't allow the inswing doors to open much past 90 degrees without hitting the inside trim. I'm still puzzling how I'm going to mount them- maybe cut the foam away and cast a concrete sill? The front door is under a deep porch, so it will never see weather, but the back door will get rained on. Our SC climate is mild, so I'm not worried about insulation; just making a durable and weather-resistant installation.

No your not reading it wrong. This is for a hot water floor slab that is supported by a standard wood floor system.





If you wanted to put the door on just the floor sheathing it might look like this. door_sill_on_sheathing.pdf


And if you want to put it on a slab it might look like this.door_sill_on_slab.pdf

How would the EPS take the stepping weight of a human body? Also, how would one attach a threshold to foam?

Posted By jdebree on 10 Mar 2013 08:55 AM
My doors are going to be inset, since putting the frame flush with the outside wouldn't allow the inswing doors to open much past 90 degrees without hitting the inside trim. I'm still puzzling how I'm going to mount them- maybe cut the foam away and cast a concrete sill? The front door is under a deep porch, so it will never see weather, but the back door will get rained on. Our SC climate is mild, so I'm not worried about insulation; just making a durable and weather-resistant installation.

That's why I did mine the way I did. If you look at the pics of my threshold earlier in the thread you'll see the door opening frame is set back behind the wall exterior. The door opening frame is made up of a sandwich of 2 2 x 6's with 1" foam between. That makes the overall thickness the same as a standard 2 x 6 frame wall. That way I used standard prehung doors for a 2 x 6 wall. I can post a pic of the finished doorway if you want.

My doors swing all the way inside,  the inset design I used worked quite well, and I think they look pretty decent.

You haven't constructed the walls yet, right?

Posted By dmaceld on 11 Mar 2013 02:36 AM

That's why I did mine the way I did. If you look at the pics of my threshold earlier in the thread you'll see the door opening frame is set back behind the wall exterior. The door opening frame is made up of a sandwich of 2 2 x 6's with 1" foam between. That makes the overall thickness the same as a standard 2 x 6 frame wall. That way I used standard prehung doors for a 2 x 6 wall. I can post a pic of the finished doorway if you want.

My doors swing all the way inside,  the inset design I used worked quite well, and I think they look pretty decent.

YES, please post a pic of the finished doorway.

Thanks!

Yes, I'd like to see a pic. My walls are built, but no sub-frame for the door yet. I have room for a single 2-by on each side and the top. I ordered the doors for a 2X6 wall. I haven't yet decided how to finish the area outside of the door at the side and top. The siding will be Hardie board, but I won't wrap it around into the door reveal. I guess I could either cover it with Hardie panel, or smooth stucco.

Posted By jdebree on 11 Mar 2013 07:01 AM
Yes, I'd like to see a pic. My walls are built, but no sub-frame for the door yet. I have room for a single 2-by on each side and the top. I ordered the doors for a 2X6 wall. I haven't yet decided how to finish the area outside of the door at the side and top. The siding will be Hardie board, but I won't wrap it around into the door reveal. I guess I could either cover it with Hardie panel, or smooth stucco.

jdebree - The 2x's should give you room to screw mount the door through the nail flange but it does make it a little more difficult to detail that area to a weather tight finish. Remember that Hardie siding should be 2" above any surface that can hold snow or rain. If you are using smart board or the like for battens, you could use them on the sides of the door openings as well. Your door supplier should be able to supply you with aluminum door sill extensions. You should detail the top outside edge of the door opening as a drip ledge to prevent water running down the wall face from back tracking on the door soffit and getting behind the nail flange.