Choosing a Patio door sill configuration
Hi all, I’m reviewing a window/door package and need to choose between many patio door sill configurations. One manufacturer, Innotech, offers 5 different configurations for triple pane outswing hinged doors (drawings attached), for my rough opening of ~10’ wide. Innotech makes extruded U-pvc frames with integrated steel support for large openings.
I’m trying to find a compromise between energy efficiency and easy access. I don’t need passive house, but overall I’m going for pretty efficient for my zone (marine 4c). So triple seal is nice but not necessary.
I also don’t need to be ADA compliant, but we are going for zero-threshold door (or very close to it) so that walking across is comfortable and not a trip hazard for all ages.
An Interior slab will connect to a perimeter stem wall which is recessed 2” at the patio door. Outside will be a stone patio. I had planned to place 1” of rigid foam below the door sill to avoid the thermal bridge, but the thick U-pvc door frames may not allow this AND a zero-threshold transition.
As I look at the architectural drawings, the high performance sill seems a bit hazardous with the 1.5” drop across the sill, or at least a bother to navigate.
I’m just looking for any insight or recommendations for a reasonable choice. Thanks!
Adam
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I had read on some GBA threads that a single short step can be a trip hazard so I worried that the 1.5” drop in the sill transition would also be a problem. Anyone or their clients have experience living with this type of sill? Thanks!
Adam
Adam,
Pretty well every exterior door I've installed in a house has had a 1 1/2" threshold. Single steps become a problem when they aren't clearly visible, or are in areas - like a sunken living room - where they aren't anticipated. Everyone expects to step over a sill when they enter or leave a house.
I'm with Malcolm; 1 1/2" is pretty normal. I've had 3" sills for high-wind areas that needed to be recessed but otherwise were not a problem.
Great, thanks so much guys. I’ll then have room for a 1” thermal break below the sill (and still be close to flush with the interior slab). Would you feel comfortable installing a heavy patio door directly on top of a strip of foam (that is, without 2x framing material on top of the foam)? I thought of going with high density EPS, but there seem to be more thermal break sill products on line, such as from Source2050 for ex. Any experience with these?
Adam
Adam,
I'm risk-adverse enough I'd probably interrupt the foam with 1"x1" shims every 24" or so.
Ah, great idea for not too much of an energy penalty
I would prioritize a drainable sill pan over reduced thermal bridging, with closely spaced shims, either plastic or wood. Just be sure the interior is air-sealed. And check the installation instructions; full support is sometimes required for a warranty, but you can decide which is more important.
If you decide to prioritize insulation, Source 2050 is a good resource and I would have no problem using one of their foam options. Just not the 100kPa one made for window sills; you want more like 1,000 kPa (±150 psi)
Thanks Michael, I definitely want to prioritize air/water management. Does this become more difficult with a foam strip for a thermal break? I’ve attached my basic patio sill plan, (one version with CEI). Im guessing the risk here that the door would damage the tape and dig into the foam?
Is there a material you would recommend, such as mastic, or a plastic sill pan over the foam?
Appreciate the help,
Adam
This is one of those situations without one right answer, as I'm sure you realize. The door won't damage high-psi (or kPa) foam, but the foam won't allow water that managed to get inside to drain.
A lot of people, including Passive House people, go with the "full barrier" method, which is to make the window or door exterior totally impervious to water infiltration; in that case, a solid block of foam would work. Except for the handful of situations where water might get through to the sill pan, in which case you need to provide a way for it to drain. With your details, if you held the backdam 1/4" away from the door, and you cut several grooves into the bottom of the foam, I think that would give you the best of both approaches.
My tilt and slides have a secondary extruction about 1.5" tall along the bottom for extra rigidity, so an even bigger step. I never noticed it.
Since these are not regular door sills, you are never stepping on it (or you really should not), so insulation under it is less of an issue. The bigger issue is trying to keep everything nice and flat, camlock doors a very unforgiving for misalignment. Just for that reason, I would mount onto something very solid.
As someone who is likely looking forward to an old age in a wheel chair lumpy door sills are very much in my awareness.
For many other people the wheelchair comes as a surprise.
I suggest preparing for it in advance.
Getting rid of the 1.5” trip hazard is critical. Commercial solution is to drop the exterior slab to below the height of the notch; make this slab a drainage plane then add pedestals and pavers or alternatively bring height up with mud-set pavers over a drain board. It can get complicated to ensure the drainage goes away from the building. In any case, the notch in the stem wall should be waterproofed and should not be a low point and have water sitting in there.