Screed before walls….

[G and J]

I’m having an insulated beam and block ground floor.   I’ll happily set out my reasoning if peeps are interested, but….
 

What downsides are there to putting in the insulation/dpm/UFH/concrete screed from a lorry before I build me walls?

 

The fibre reinforced sand and cement screed can be poured from a lorry and once cured it will give us a good base to build off of.

 

It’s not my original idea, I stole it from a buildhub stalwart, but I think it’s a good one.  But practically, what issues might it cause?

[nod]

You can put your screed down anytime once you are watertight 

If it’s sand and cement it won’t be pours More likely barrowed in or blown in 

[JohnMo]

2 hours ago, G and J said:

concrete screed

Concrete, not really screed. We did a quite high slump so it could be pumped.

 

You need to have all drainage pipes positioned for toilets, sinks, showered etc. I used waste bits of 100mm thick PIR as formers to exclude concrete where I was uncertain, back filled later as needed.

 

You need any block work in place up to finished ground floor level.

 

You need to pre-position UFH manifold. All pipes need to be protected from freezing if the container water. So either air test or water/antifreeze solution.

 

Do not let UFH pipes goes under walls, as you are likely to someone put a hole in the pipe.

 

So photo, all the wall sections are removable and we're moved during the job. Have shown, UFH manifold, main electrical cabinet and floor formers to exclude concrete. We used a pump to get concrete from A to B.

 

[saveasteading]

2 hours ago, G and J said:

What downsides are there to putting in the insulation/dpm/UFH/concrete screed from a lorry before I build me walls?

Weather. If it rains it can be ruined. Can't do it on a freezing day.

If it is hot or windy it can dry too fast. That can be controlled with polythene, but isn't ideal and you may get marks.

You need to be flexible.

[JohnMo]

Thing I missed, when it's wet and there is a freeze overnight, the floor takes days to defrost, especially if you are well insulated and no side thermal bridging.

[G and J]

Thanks folks.  It seems to me the risk vs benefits don’t look good for our build.  I’m not as brave as JohnMo.  So it’s back to either a temporary floor or simply sticking with a standard bnb floor.