Detailing Wall-plate for 10° Monopitch....

[Mulberry View]

I've built my Nudura walls up to full plate height, with the idea that the Wall-plate will be installed along with the concrete and will match that height, essentially leaving the insulation all the way up.

 

 

However, the plywood deck will, I assume, be attached on top of the Posis and oversail onto the Wall-plate. So, how best to fix it?

 

I think my favourite way at the minute is to use Coach Bolts with the heads recessed into the Wall-plate, bolted on the back, then with a Nut/Washer/Nut at the bottom of the thread to anchor it if necessary. This would be pressed into the wet concrete and aligned with a laser/string. Of course I would not be able to cram the Wall-plates down once the concrete is cured, but is this necessary?

[Conor]

Float the concrete to the right height. Let it set. Then fix the wall plates down after using LONG concrete bolts or chemical resin bolts. I think the bolts our guys used were something like M12, 200mm long. His impact wrench was bigger than my SDS drill! He had had the face of the timber machined to the roof angle. Also left the insution on the inner leaf higher than required, it was.later.trimmed down to the tight height, again, matching the roof angle. Meant less filling on the inside.

Edited December 5, 2023 by Conor

[ChrisJ]

Engineer to approve, but your posijoist system will complete the diaphragm of the structure, typically you have straps on top of the posijoist which too will flyover the top of the ICF and need fastening to the top of the ICF wall. Your plywood can simply flyover for a smooth surface for the roofing membrane to be on. I'd suggest leaving the posijoists 5mm higher then the ICF wall, no one gets the concrete perfectly flat or smooth for the plywood to sit accurately on, laydown a nice spread of spray foam before putting each sheet of plywood over and then use some concrete screws to fasten the edge to the concrete, just snug them, don't over tighten to distort or skew the plywood. once the spray foam has cured, trim any extra that has expanded past the face of the exterior ICF wall

 

Looking at your picture, the angle of the ICF cut, embedding a 6x2 to be flush with the top of the ICF will be almost impossible as the webs are in the way in several spots, if you cut them to make proper space, you will need to do additional bracing prior to pour so as the ICF block doesn't flare out from the concrete pressure during the pour

[jamiehamy]

We did something similar. The first time, we laid the wallplate on the poured concrete, this time we simply got the level and them secured the wallplate using resin bolts. As you can wee, we'd left enough ICF to be trimmed down flush to the top of the joists, then when the OSB went on, we used air tight foam, as well as between the joists and the ICF. 

[jamiehamy]

view from inside. 

[Mulberry View]

6 hours ago, jamiehamy said:

We did something similar. The first time, we laid the wallplate on the poured concrete, this time we simply got the level and them secured the wallplate using resin bolts. As you can wee, we'd left enough ICF to be trimmed down flush to the top of the joists, then when the OSB went on, we used air tight foam, as well as between the joists and the ICF. 

 

That looks good and not entirely different from my setup. I do not have a soffit as such, so do not have the oversailing timbers.

 

As far as you having installed the wall-plates both during and after the pour, which was your preference and why please?

[jamiehamy]

2 hours ago, Mulberry View said:

 

That looks good and not entirely different from my setup. I do not have a soffit as such, so do not have the oversailing timbers.

 

As far as you having installed the wall-plates both during and after the pour, which was your preference and why please?

Preference is after. The gables are the tricky bit and trying to get concrete to go off but not too much whilst having it all plumb/straight at the same time and then get a wall plate and j bolts on was stressful. Doing the wall plate post pour was arguably more work (drilling )but was easier to do, and easier to do right. 

[Gus Potter]

Hiya folks.

 

I do like the ICF concept but we are self builders here, not McAlpines ect ( major Contrators)  who have Engineers on site checking levels etc. It's self building and we have limited resources.

 

Ok a few options considering what you have to work with.

 

First is ICF.. you have been pouring all day..worrying about bracing and burst out, getting the compaction right and the concete coming on time, it may be raining and windy.. by the time you get to the top of the wall everyone is knackered on site.. the last thing you want to do and are just too tired to do is to finish the top off or start thinking about bedding in fixings. Don't even try to do this at the end of the day.

 

I would keep the top of the concrete 0- 10mm low if you want to "go with the computer"... if you want to be pedantic... not my favoured option.

 

You need to tie the roof to the top of the wall. You can use Simpson L brackets for this which are good for uplift and shear loads. For Posi joists you can introduce a vertical noggings /dwangs  if not already provided to give you a nail fixing for the brackets.

 

I would keep the concrete 55 + /- 5 mm low and then later bed and tie down at your leisure a traditional timber wall plate 95 x 45  C16 grade timber on that. You can get it level, fix it down easily and then you can get your expensive posi joists spot on level. I may come over as a philistine but I see this all the time where.. the computer drawing says yes.. but on site at the end of the day, messing about with concrete, with local builders the mood music is.. "NO CHANCE MATE"

 

I know you can go on ICF web sites and the posi  joist web sites and it all looks sooo easy on the computer.. but on the ground it is not so. The trick is to identify where things go wrong and actually design and plan for the "shit that happens"

 

Cut yourself some slack.. keep the concrete low and introduce a get out of jail free card for youself by way of a traditional timber wall plate as above.

 

This way you actually get more control over the quality between the two interfaces and design packages as you are able to adjust the wall plate height and at a push it's thickness youself.. you get a fresh start with the roof levels. This can be a bit more work but it it can avoid disputes which are really stressful..  you create a zone where you can just "sort it yourself" and you make a clear break point between the roof and wall work packages if need be.

 

This is unique to the self build thing.. we need to often balance personal stress / family pressure vs the build. I see this and have in the past been a self builder so the above is based on my own experience. You know you have the ability so if you can apply that to make a clean break between the work packages / last lot of contractors it can help a lot. Some Contractors are great and you want to keep wqorking with them.. others it a relief to see the back of them (I'm being polite here)

 

 

 

 

 

 

 

 

 

 

 

 

[Mulberry View]

7 hours ago, Gus Potter said:

Hiya folks.

 

I do like the ICF concept but we are self builders here, not McAlpines ect ( major Contrators)  who have Engineers on site checking levels etc. It's self building and we have limited resources.

 

Ok a few options considering what you have to work with.

 

First is ICF.. you have been pouring all day..worrying about bracing and burst out, getting the compaction right and the concete coming on time, it may be raining and windy.. by the time you get to the top of the wall everyone is knackered on site.. the last thing you want to do and are just too tired to do is to finish the top off or start thinking about bedding in fixings. Don't even try to do this at the end of the day.

 

I would keep the top of the concrete 0- 10mm low if you want to "go with the computer"... if you want to be pedantic... not my favoured option.

 

You need to tie the roof to the top of the wall. You can use Simpson L brackets for this which are good for uplift and shear loads. For Posi joists you can introduce a vertical noggings /dwangs  if not already provided to give you a nail fixing for the brackets.

 

I would keep the concrete 55 + /- 5 mm low and then later bed and tie down at your leisure a traditional timber wall plate 95 x 45  C16 grade timber on that. You can get it level, fix it down easily and then you can get your expensive posi joists spot on level. I may come over as a philistine but I see this all the time where.. the computer drawing says yes.. but on site at the end of the day, messing about with concrete, with local builders the mood music is.. "NO CHANCE MATE"

 

I know you can go on ICF web sites and the posi  joist web sites and it all looks sooo easy on the computer.. but on the ground it is not so. The trick is to identify where things go wrong and actually design and plan for the "shit that happens"

 

Cut yourself some slack.. keep the concrete low and introduce a get out of jail free card for youself by way of a traditional timber wall plate as above.

 

This way you actually get more control over the quality between the two interfaces and design packages as you are able to adjust the wall plate height and at a push it's thickness youself.. you get a fresh start with the roof levels. This can be a bit more work but it it can avoid disputes which are really stressful..  you create a zone where you can just "sort it yourself" and you make a clear break point between the roof and wall work packages if need be.

 

This is unique to the self build thing.. we need to often balance personal stress / family pressure vs the build. I see this and have in the past been a self builder so the above is based on my own experience. You know you have the ability so if you can apply that to make a clean break between the work packages / last lot of contractors it can help a lot. Some Contractors are great and you want to keep wqorking with them.. others it a relief to see the back of them (I'm being polite here)

 

 

 

 

 

 

 

 

 

 

 

 

 

That's all understood Gus and I have a feeling you're right. My mind was set that if I am to leave the top of the concrete in a suitable condition for later adding wall-plates, that would mean working to get it nice and flat/level and by the time I've done that, I might as well have installed the wall-plates as it didn't 'feel' in my head as being much more work.

 

I am a precision person, I would be gutted if I didn't get to hear that re-assuring flat-line beep from my laser level when the Posis go in, but that's a rabbit hole I've already allowed myself to go down.

 

So, when installing the wall-plates, is it acceptable for them to only be touching the concrete at the fixing points, if packing is necessary? Or is there another way? Do I leave the concrete deliberately low and make up the deficit with my own cement/concrete mix later on whilst doing the fixing?

[jamiehamy]

7 hours ago, Gus Potter said:

Hiya folks.

 

I do like the ICF concept but we are self builders here, not McAlpines ect ( major Contrators)  who have Engineers on site checking levels etc. It's self building and we have limited resources.

 

Ok a few options considering what you have to work with.

 

First is ICF.. you have been pouring all day..worrying about bracing and burst out, getting the compaction right and the concete coming on time, it may be raining and windy.. by the time you get to the top of the wall everyone is knackered on site.. the last thing you want to do and are just too tired to do is to finish the top off or start thinking about bedding in fixings. Don't even try to do this at the end of the day.

 

I would keep the top of the concrete 0- 10mm low if you want to "go with the computer"... if you want to be pedantic... not my favoured option.

 

You need to tie the roof to the top of the wall. You can use Simpson L brackets for this which are good for uplift and shear loads. For Posi joists you can introduce a vertical noggings /dwangs  if not already provided to give you a nail fixing for the brackets.

 

I would keep the concrete 55 + /- 5 mm low and then later bed and tie down at your leisure a traditional timber wall plate 95 x 45  C16 grade timber on that. You can get it level, fix it down easily and then you can get your expensive posi joists spot on level. I may come over as a philistine but I see this all the time where.. the computer drawing says yes.. but on site at the end of the day, messing about with concrete, with local builders the mood music is.. "NO CHANCE MATE"

 

I know you can go on ICF web sites and the posi  joist web sites and it all looks sooo easy on the computer.. but on the ground it is not so. The trick is to identify where things go wrong and actually design and plan for the "shit that happens"

 

Cut yourself some slack.. keep the concrete low and introduce a get out of jail free card for youself by way of a traditional timber wall plate as above.

 

This way you actually get more control over the quality between the two interfaces and design packages as you are able to adjust the wall plate height and at a push it's thickness youself.. you get a fresh start with the roof levels. This can be a bit more work but it it can avoid disputes which are really stressful..  you create a zone where you can just "sort it yourself" and you make a clear break point between the roof and wall work packages if need be.

 

This is unique to the self build thing.. we need to often balance personal stress / family pressure vs the build. I see this and have in the past been a self builder so the above is based on my own experience. You know you have the ability so if you can apply that to make a clean break between the work packages / last lot of contractors it can help a lot. Some Contractors are great and you want to keep wqorking with them.. others it a relief to see the back of them (I'm being polite here)

 

 

 

 

 

 

 

 

 

 

 

 

Well said!