Lagging of pipes under concrete floor.

cheekyrascal · 10 Mar 2007

We have a bungalow with an extremely uneven and out of level (concrete) kitchen floor, complete with unsightly heating pipes running along the skirting boards.

We are going to break up and replace the floor(for tiling) so will take the opportunity to replace the heating pipes and put new ones below the new floor.

My query is about insulating the pipes. For about 10ft all four pipes (2 rads in 10mm copper) will all run together. Do they need individually lagging or is it OK to bunch them together?(which would make it much easier to get them through an existing wall)

Many Thanks.

gas4you · 10 Mar 2007

I can't see any reason to not bunch them together and cover in 28mm tubulsr hairfelt. Make sure they are all covered so concrete cannot touch any pipe work in copper.

cheekyrascal · 10 Mar 2007

Thanks gas4you.

Is hairfelt the old fashioned type of lagging which came in rolls which you wrapped around the pipes?

It sounds just like the old stuff I recently threw out!

gas4you · 10 Mar 2007

yes, but the tubular type is in fact a tube of it that just slides over pipes instead of having to wrap around pipe work. Only costs about £7 per roll, 21M long

cheekyrascal · 10 Mar 2007

Many thanks for your help gas4you.

doitall · 10 Mar 2007

Interesting to note the inappropriate use of hair felt lagging, and probably about the worse stuff you can use.

The floor screed is wet when layed and hair helt is not waterproof, it will not protect the copper pipe from the cement

gas4you · 11 Mar 2007

All the tubular hairfelt I use has an inner liner made of polythene/plastic. Last time I check this wasn't porous

scaby · 11 Mar 2007

I could be wrong (it has been known) but i thought all pipes in floors had to be accessible, either ducts or pipe in pipe for plastic, except gas which you can wrap in denso tape and bury in the screed,(copper of course)

doitall · 11 Mar 2007

scaby said:
I could be wrong (it has been known) but i thought all pipes in floors had to be accessible, either ducts or pipe in pipe for plastic, except gas which you can wrap in denso tape and bury in the screed,(copper of course)

Only applies to Hot and Cold water services.

namsag · 11 Mar 2007

With doitall on this point we always wrap the pipe first then put the lagging on as although it does have a membrane in it, it is not completely water/cement proof

gas4you · 11 Mar 2007

Thanks. I always assumed membrane was waterproof

I will certainley take on board both yours and doitall comments next time I lay heating pipes in screed. Yet again I've learn't something from here

doitall · 11 Mar 2007

Use Unipipe or plastic coated soft copper.

gas4you · 11 Mar 2007

I cannot stand using unipipe

But plastic coated copper is good

doitall · 11 Mar 2007

gas4you said:
I cannot stand using unipipe But plastic coated copper is good

Unipipe is brilliant stuff and easy to install.

gas4you · 11 Mar 2007

I agree that it is a very good product, but I dont kike the fact it is all odd sizes. Also around here they will only order a minimum of £150 worth at a time therefore I would not be using enough to order this amount

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Lagging of pipes under concrete floor.

scaby

namsag

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