Wondering any opinions on setting SIPS panels on an ICF brickledge? Is this a silly idea? There seems to be no perfect way to eliminate thermal bridging when the SIPS need to have support at their outer osb edge. I am looking to use timber frame with 8x8 beams and plan on radiant concrete floor. My attached picture shows the sill plate cantilevered out over the edge of the brick ledge by a couple of inches.

One has to be careful about placing too much weight on a brick ledge, especially an ICF brick ledge.  Calculate the weight of the SIPs per linear foot and compare that to what the brick ledge can carry.  In a few cases, I have been told by ICF manufacturers that I could not place certain heavy items on an ICF brick ledge.  Although brick is heavy, all of the weight does not rest on the brick ledge.  The brick ties will carry some of the weight.  Depending upon the type of SIP, more than likely its weight will not exceed the capacity of the brick ledge.  But do verify.

Yes in similar fashion to the brick ties, the SIPS could be screwed to the timbers. I will get all of the weights calculated, but I have not seen the numbers that say just what a brickledge will support. It seems that foam and osb would be far less than brick. Also some builders use the brickledge inside out to support the floor joists. That has got to be a lot heavier than foam. I have not shown the rebar in the ledge or the timberlinks holding the oak timbers down, or the concrete anchor holding the treated down.

Actually, that's a great idea. Polycrete does not make a haunch-like brickledge as is commonly found with most ICFs. The system is most often used in commercial applications, so it uses a taper top form that tapers down to 5/8" foam. You can even have the taper on both sides to widen your concrete base. Send me your contact info in a private message and I will send you all the pertinent info.

Sorry, accidental double-post. Wish there was a way to delete a post.

Only the administrator can delete a post.  Otherwise, a lot of posts would be deleted.

I've wondered wat that !Alert icon does. :-) Is it like pulling the fire alarm, or more like the FBI alert on VCR's

If you were to use a Taper Top on the inside and Brickledge on the outside, you should have enough concrete to support your timbers and keep the SIP on top of the Brick Ledge.

Doubt you will have to worry too much about the weight of the SIP, since the timbers will likely be carrying the roof (I could be wrong on this). The brick ledge will only be holding the weight of SIP itself (some weight transfered to Timber by screws/ties).

If you were to use a Taper Top on the inside and Brickledge on the outside, you should have enough concrete to support your timbers and keep the SIP on top of the Brick Ledge.

Oh good idea! I could just cut the brickledge form myself on the inside to make it a "tapertop brickledge". It will just involve moving the timbers inward 2 inches ... or the whole footing/foundation outward 2 inches.

Seems like someone would have tried this before with the cantilever situation though. Perhaps I could squeeze 1/2" foam below the drywall between the radiant floor and the sill plate to buffer the thermal bridge a little.

OK Plan B

kb - I think I would put a thermal break between the radiant floor and the ICF concrete. In all cases there would be some heat loss from the floor to the wall. In your case you only have 5/8" foam stopping heat loss from the floor to outside. Furthermore, now you only have 5/8" on the inside as well. In all thing ICF, try to encapsulate all the concrete in at least 2" of foam. Because concrete is so conductive to heat it effects the whole wall when you have a weak spot like the top form. Also with the radiant heat this will be your highest delta T.

Some manufacturers (I know NUDURA for one), have the option of ordering a Taper Top/Brick Ledge form from the factory. This would save you from manufacturing the Taper Side on site from a standard panel.

I would put a thermal break between the radiant floor and the ICF concrete

Good idea I haven't seen a detail of that, but now I will look for some.

WRT the field cut taper top, I would only need to do it where the posts land, corners and once every 12 ft or so, so the rest could be nontaper top. That would keep my manual cutting to a minimum as well as a bit less concrete.

I haven't found EPDM sheet/gaskets that are 1/2 thick yet either. I suppose I could use either EPE or plain old pink foam. Maybe foam would work as the thermal break between the floor and the icf. Not sure what would be best for that yet. I'll look into it some more. Geofoam or EPS with the higher density rating might do the trick.

kb - have you considered using pilasters on the inside of say 12" x 12" for each of the timber frame bents? You could set the columns on them and still have room to set the sips on the wall and not worry about the brick ledge. If you used a 6" core instead of an 8" core the money you save on the concrete should offset the time it would take to build the pilasters.

FBBP, everything is worth considerring. THe KISS principal probably had me do the 8' walls. I will look through all of my notes and see what other reasons I had decided on 8". I suppose if I had the SIPS just sit on the 6" ICF (11"OD) I could just build out(in) a 3 sided box for each post in the bent. I would have to consider the rebar mods for that too.

For that matter I could pobably do 6" walls up to the top layer and then expand to the 8" tapertop brickledge layer.

http://www.integraspec.com/documents/Pilasters_Slideshow.pdf

FBBP, now that is some heavy duty design load.

At least I finally found a Brick Ledge Factored design load of 16KN/m (including typical rebar stirrups)
So, converting that to units that I understand..
1" = 0.0254 m
1 lb = 4.448222 N = 16 oz

16 kN/m to lbs/inch: ( 16000 N/m x 1 lb/4.44822 N x 0.0254 m/1 in) = 91.37 lb/in

So the brickledge can hold 91.37 lb/in...seems like that will cover the weight of the SIPS and then some.

kb - is this just a stem wall or is there unrestrained section in the wall?

FBBP, This is intended as the top level of icf blocks in a 9 ft foundation wall. I have included a Hambro type joist in this drawing. I could go with speedfloor, Hambro, ClarkDietrick, or metawood. I don't see where I could put in a thermal break between the floor and the icf though.