New central heating system- type/size of pipes under floor

[Zebra579]

I am having an inch thick solid oak tongue and groove flooring laid onto joists, over insulated concrete on the whole of the ground floor. First I must lay central heating pipes. It's an entirely new system.
Is it best to use plastic or copper for central heating? What size? Should they be wrapped in anything?
Once this floor is laid it won't be able to be lifted to gain access. I understand that it's a bad idea to bury a join where it will no longer be accessible. But I also understand that a central heating system is laid in a kind of "branch" system, rather than in a "ring" sort of system, with the flow teeing off to each radiator, rather than looping from one radiator to another. Therefore joins under the floor seem unavoidable. What is the answer?
Finally, is it legal to lay your own central heating pipes and then just have the Gas Safe plumber connect them up when he installs the boiler?
Many thanks
zebra

 

[petertheplumber12]

There is nothing wrong with using barrier plastic pipe, and use De-zincked brass compression fitting for joining with the metal inserts, cover the teed brass comp fittings with some plastic sheet, put a compression coupling on the end near a radiator and bring 15mm copper up through screed floor to each end of rad. Also tape round copper pipe to protect it from the cement up to just above floor level then you can remove surplus tape once screed is down. Run a tee of at ground level drill thro' the wall and run a plastic pipe out side with an isolating vale or stop tap as a system drain point. I did that for a job for a surveyor (the drain off). The pipe doesn't need insulating since any heat through the floor is useful anyway. Good luck and merry xmas.

 

[petertheplumber12]

By the way anyone can do any plumbing even gas pipes but they cannot connect them to gas. but water anyone can.

 

[winston1]

It is a myth that you have to be gas safe registered. That only applies if you are doing work for payment. For doing you own work there is no requirement to be registered.

 

[Agile]

Thats all a good idea Mr Zebra!

You will keep your smaller animal colleagues , the rodent family, happily chewing through the plastic pipes conveniently located under the floor!

 

[doitall]

Manifold somewhere central, then run a pair of 10mm pipes to each rad.

Minimum joints if any, I would also try and lag as much as posible unless it's an insulated floor.

 

[CBF]

There is nothing wrong with using barrier plastic pipe, and use De-zincked brass compression fitting for joining with the metal inserts, cover the teed brass comp fittings with some plastic sheet, put a compression coupling on the end near a radiator and bring 15mm copper up through screed floor to each end of rad. Also tape round copper pipe to protect it from the cement up to just above floor level then you can remove surplus tape once screed is down. Run a tee of at ground level drill thro' the wall and run a plastic pipe out side with an isolating vale or stop tap as a system drain point. I did that for a job for a surveyor (the drain off). The pipe doesn't need insulating since any heat through the floor is useful anyway. Good luck and merry xmas.

compression fittings under a floor that will never see the light of day again, what a fantastic idea, & i don't think screed was talked about at all

personally if the floor is going to be inexcessible i would think about drops from above to the rads & box the pipes in

 

[CBF]

It is a myth that you have to be gas safe registered. That only applies if you are doing work for payment. For doing you own work there is no requirement to be registered.

yep another fantastic idea, my god this thread is full of them

 

[Zebra579]

Hmmm. OK. Compression fittings under screed doesn't sound like a good idea. But a drain off at under-floor level is perhaps a good idea.
Thanks for the confirmation that any unregistered person can do the pipework. I won't try to do the gas work in any case.
I don't think rodents will be a problem, it's a solid floor so there's nowhere for them to get in. (It's Miss Zebra by the way
Not practical to do radiator drops from above.
But a manifold somewhere central and then a pair of 10mm pipes to each rad, that sounds like a good idea. Do you mean plastic, doitall?