Pipes in concrete/screed floor

[HawkWhiteFinger]

Hello.

I should know this, but haven't done it in a screed before.

Have one radiator to connect to an existing system for an extension.

The extension has a concrete floor and the pipes to be laid will be buried in screed.

What's the best method to adopt? I was intending to use copper and have thought about what I might be able to sleeve it with.

Any suggestions? Thanks.

 

[Best]

Plenty here done for years just with Armaflex or cheaper insulation, at best.
Supposed to run ducts (ideally around edge of floor)

 

[Best]

Will the floor not have Kingspan insulation board on top of sub floor first?

 

[HawkWhiteFinger]

Will the floor not have Kingspan insulation board on top of sub floor first?

It will yes.

 

[Best]

I worked on a job where the insulation board was cut around the pipes that were insulated with Armaflex. All about same depth of the insulated pipes. Then a thinner sheet of insulation board was put over the top of entire boards including pipes.

 

[HawkWhiteFinger]

Good idea, I can always channel in the celotex and then cover up. Thanks.

 

[Best]

Good idea, I can always channel in the celotex and then cover up. Thanks.

If the insulation board was put in two base layers, - say 2 of 50mm instead of 1 of 100mm, or whatever, then you can sometimes put the first layer down and run the pipes on top, cutting a piece out if you have to cross below to tee off at any points. That way the insulated pipes are also sitting on the insulation. Then you cut the next layer of insulation board to the pipes and a final third layer of insulation board covering whole floor.
It is actually better insulation to use 2 foil coated insulation boards rather than 1 heavier board obviously because of extra foil sides
I think 15mm pipes tend to be at least 50mm thick including Armaflex, so you might need next size up of board to be at least same level as the pipes it surrounds.

 

[RDS]

How about Hirfelt tubular lagging??

 

[ShaunCorbs]

How about Hirfelt tubular lagging??

as its pourris no

 

[rpm]

as its pourris no

You mean Porous yes ?

 

[ShaunCorbs]

You mean Porous yes ?

Yes that's the one never know how to spell it 😀

 

[rpm]

Yes that's the one never know how to spell it 😀

I don`t normally jump in on spellings, think it`s kind of rude TBH, thought maybe you were texting whilst waiting for traffic lights to change or something like that.

 

[ShaunCorbs]

I don`t normally jump in on spellings, think it`s kind of rude TBH, thought maybe you were texting whilst waiting for traffic lights to change or something like that.

Naa I just suck at spelling lol

 

[RDS]

Porous yes, but in a dry screed mix cant really see much of a problem and haven't seen a problem either. I have often worked on existing pipes which have been lagged in hirfelt - extending existing pipe runs etc - and have never found any issues with the pipes, some of which have been in place for good 40/50 years.

Armaflex would be great but the cost is substantially more!! Never come across pipes in screed lagged with armaflex, seen plenty of pipes buried in screed with no lagging though!

 

[paulusgg]

Any thing's got to better than no lagging, job I was on a week ago had old newspaper wrapped around the pipe. Daily Sketch, August 1972!

 

[HawkWhiteFinger]

Ok chaps.

What I've done is used 25mm flexi conduit to sleeve the copper, to protect it. No insulation on it as it's above celotex boards, so it's in the warm part, just to be covered with screed.