Stud walls on screed floor?

[Benpointer]

I know SE input will be required at some point but I am just trying to get my head around this now.  

 

Planning just submitted (see pics), plans out for initial quotes with several TF / SIPS company (we'd prefer TF with cellulose fill if we can afford it).  Also trying to get an indicative quote from my preferred groundworker for the foundations.  Floor is going to be B&B + 200-300mm EPS + 70 screed with UFH.

 

Question I have is can the non-structural internal stud walls be built off the screed or will we need to build block upstands under each, with the concrete trenches, insulation detail etc. that those will require? 

 

Here are some pics:

Edited February 1 by Benpointer

[Barnboy]

I built all of my non structural studs off of the concrete slab, no trnches required.

I laid marmox blocks down 1st as a thermal break followed by a single course of std 4" blocks on edge, I then bolted my sole plates in to the 4" block, you could probably add a soapbar block onto you std block to give you more height.

If you lay everything out carefully then by the time you're insulation and screed are down you'll be up to the top of your blockwork with just the sole plate to show. 

[Conor]

I did the opposite, thermal blocks, treated sole plate, then studs. Directly on the slab, no trench underneath. This was because most of the walls were being built in block, so made sense to build the studs off the same first course of thermal blocks. 

 

That was the ground floor... For the other floors, the stud frames were built directly off the floor structure (concrete planks) and boarded, before screeding.

 

If you leave your stud walls till after the screed is down, you'll have an almighty amount of cleaning up to do of the screed before flooring.

[Benpointer]

Ok thanks guys. 

 

Still not quite sure what we should do off of our floor which is planned to be block & beam + 200-300mm EPS + 70 screed with UFH.  

 

Is it ok to fix stud walls to 70mm of screed?  If we leave the screed until after the stud walls are in what do we fit the base of the stud walls too?  Not the EPS insulation obvs.  Nor to the B&B itself.

 

It'd be helpful if we can avoid building up from the B&B under every stud, with the cold bridging issues we would have to address.

[Pocster]

I’m pretty sure I did like a dwarf wall of insulating blocks ( they were some funny size I.e quite small ) cemented to the beam and block . Damp course , timber frame and studs ontop . Then insulated floor , ufh , plastic sheet , screed . All was fine ( and still is ) 

[Mr Punter]

Yes, you can build the non-loadbearing studwork walls off the insulation / screed.

[Russell griffiths]

Non load bearing stud walls go directly onto the screed, you fix the sole plate down with a no nails type thing. 
load bearing walls need to go down to either the block n beam designed for this or down through the block n beam onto a foundation below the floor. 

all depends on the loads the wall is carrying. 

[G and J]

I like the idea of my non load bearing walls being built off of my screed, thus having continuous insulation under them.

 

But I prefer screws and rawlplugs to fix (yet another example of the Luddite in me).

 

Apart from avoiding my UFH pipes is there any reason I can’t screw me sole plates down?

[JohnMo]

54 minutes ago, G and J said:

But I prefer screws and rawlplugs to fix

These are much easier, use multi drill bits, through the wood sole plate and carry on through the screed, everything stays aligned perfectly, drop plug in place and just hammer in place. Unscrew if you need to.

 

https://www.screwfix.com/p/easyfix-nylon-hammer-fixings-8mm-x-120mm-10-pack/19157?tc=TA5&gad_source=1&gclid=CjwKCAiAzPy8BhBoEiwAbnM9O8PjSRZDZU-ltLFwyTVeMzEXZsXobLQs9-BlGsCqgey_2u3J-TayVBoCcjQQAvD_BwE&gclsrc=aw.ds

[Benpointer]

Great, thanks everyone.  

 

(Although, I have to say @JohnMo that every single time I have tried to use hammer fixings it has ended in tears - wobbly fixings, bent screws or both.)

[saveasteading]

Practically....if you lay the ufh clear of the wall position then you can drill and screw into it. I took to the new breed of Fischer plugs, but have reverted to hit-fix for sole plates...it's so easy to drill and fit in one operation. As often, well known brands often work best.

 

Engineering-wise. The load of the wall is simply its dead weight, so negligible

BUT if the stud is tight to the floor above then it will take load from it, and the screed on insulation won't be strong enough.

So leave the wall short at the top with a flexible infill. Of course it still needs fixing, so use screwed brackets to the joists to let it displace.

[Russell griffiths]

2 hours ago, G and J said:

I like the idea of my non load bearing walls being built off of my screed, thus having continuous insulation under them.

 

But I prefer screws and rawlplugs to fix (yet another example of the Luddite in me).

 

Apart from avoiding my UFH pipes is there any reason I can’t screw me sole plates down?

Don’t do it, it’s not needed. 
I put a small wall in the wrong place, crowbarring it up actually lifted chunks from the screed. 
 

[Benpointer]

3 hours ago, Russell griffiths said:

Non load bearing stud walls go directly onto the screed, you fix the sole plate down with a no nails type thing...

You mean a glue - you glue your stud wall sole plates to the screed? 

[JamesP]

@Russell griffiths As mentioned.

I glued all our stud wall to the screed using Caber D4 adhesive.

[G and J]

2 hours ago, JohnMo said:

These are much easier, use multi drill bits, through the wood sole plate and carry on through the screed, everything stays aligned perfectly, drop plug in place and just hammer in place. Unscrew if you need to.

 

https://www.screwfix.com/p/easyfix-nylon-hammer-fixings-8mm-x-120mm-10-pack/19157?tc=TA5&gad_source=1&gclid=CjwKCAiAzPy8BhBoEiwAbnM9O8PjSRZDZU-ltLFwyTVeMzEXZsXobLQs9-BlGsCqgey_2u3J-TayVBoCcjQQAvD_BwE&gclsrc=aw.ds

I like frame screws, as I’ve always called ’em.   You can get little ones nowadays too.

 

[G and J]

1 hour ago, saveasteading said:

Practically....if you lay the ufh clear of the wall position then you can drill and screw into it. I took to the new breed of Fischer plugs, but have reverted to hit-fix for sole plates...it's so easy to drill and fit in one operation. As often, well known brands often work best.

 

Engineering-wise. The load of the wall is simply its dead weight, so negligible

BUT if the stud is tight to the floor above then it will take load from it, and the screed on insulation won't be strong enough.

So leave the wall short at the top with a flexible infill. Of course it still needs fixing, so use screwed brackets to the joists to let it displace.

Hmmmmm.    Methinks I need guidance from the SE designing our foundations.   

[Gone West]

I also glued our stud walls to concrete floor using PU gel adhesive.

[Russell griffiths]

12 hours ago, Benpointer said:

You mean a glue - you glue your stud wall sole plates to the screed? 

Yep. 

[Alan Ambrose]

I think some here are talking block walls, some timber frame and others, maybe, metal frame?

[saveasteading]

20 minutes ago, Alan Ambrose said:

some here are talking block walls, some timber frame and others, maybe, metal frame?

All talking stud I think. Nobody talking blocks ot any word like that.

 

You've made me think though. A metal stud wall might be so weak that it crushes under any load from the floor above and doesn't transfer it to the screed and the insulation supporting it.

That doesn't seem proper though as there then wouldn't be a seal at the head.