Which joists for new build Posi vs I joist?

[Ruggers]

Good to know that, just have to ensure they are correctly sealed for MVHR purposes. Posi & I joists looks awkward for fitting copper pipe without multiple couplers.

 

[oldbutnotdead]

You can use masonry joist hangars if you're worried about getting an adequate room seal. And don't even think about notching I beams or the other ones- wouldn't work well. New builds of course they'd be throwing plastic tube through them so not a problem

 

[Ruggers]

You can use masonry joist hangars if you're worried about getting an adequate room seal. And don't even think about notching I beams or the other ones- wouldn't work well. New builds of course they'd be throwing plastic tube through them so not a problem

Certainly wouldn't be notching posi or ibeams that's an instant fail.
I do prefer copper pipes over plastic though, there's people for and against but I know copper pipe & fittings stand the test of time, it's the rubber o rings in plastic fittings I'm not 100% about. I might have to bite the bullet and do plastic all over. I feel the modern joists force you to use plastic now just for it's flexibility.

 

[Leofric]

If you are bothered about running services through the joists go for the open web type. Whether copper or plastic pipe is another matter but if you are using plastic heating pipes it should be the oxygen barrier type. Joists at 600mm centres require minimum 22mm thick chipboard floor panels.

 

[Ruggers]

If you are bothered about running services through the joists go for the open web type. Whether copper or plastic pipe is another matter but if you are using plastic heating pipes it should be the oxygen barrier type. Joists at 600mm centres require minimum 22mm thick chipboard floor panels.

Do you have any experience with open webbed or any joists being spaced at 600mm. I've only done them at 400 in the past which have been fine. Changing a full house from 600 to 400 centres would add a lot onto the cost so I'd prefer to avoiding unless it's strongly advisable.

Is the oxygen barrier pipe something new of the last fews years? I've only used the standard grey in the past but for supplying tap water only coming from copper.

 

[John D v2.0]

There are pros and cons of plastic pipe, copper does fail eventually too, the main one to get rid of is tap Flexi tails.
Personally i like copper when it's a project piece or where space is tight but for flexibility and ease of use you can't beat plastic.
Barrier pipe has been around a long time it's got a foil layer i think and keeps oxygen out. All the speed fit I've bought has been barrier pipe as standard though, you can see a blue ring on the cut ends.

 

[Ruggers]

Thanks John, I won't go off topic & will stick to info. for joists but I'll have a read up on the different types of pipe if it's going to be used for heating & check if I can use one type or require different for tap water and central heating. You wouldn't think air could get into normal plastic pipe.

 

[Leofric]

Do you have any experience with open webbed or any joists being spaced at 600mm. I've only done them at 400 in the past which have been fine. Changing a full house from 600 to 400 centres would add a lot onto the cost so I'd prefer to avoiding unless it's strongly advisable. - Thought you were talking about joists at 600mm centres , but joists have usually been at 400 crs on jobs I have worked on.
Open web started becoming more popular for floor joists with builders we specified for but have specified all types of joists. Used to just do 200 x 50mm softwood joists at 400mm centres for all first floors at one time unless the span exceeded 4m.
Is the oxygen barrier pipe something new of the last fews years? I've only used the standard grey in the past but for supplying tap water only coming from copper.

- Oxygen barrier pipe has been around years. Builder of my house built 1997 used 10mm non oxygen barrier Hep2O plastic pipe for central heating and we had 3 radiators off by the time I had it replaced with minimum 15mm oxygen barrier pipe within first floor and 15mm copper pipe from 1st down to ground floor. British Gas would not cover microbore non oxygen barrier pipe on service contract and I took it up with the housebuilder, NHBC, sub contractor who installed central heating, Hepworth who produce Hep20 and even Sentinel who produce the corrosion inhibitor but didn't get anywhere banging my head against a brick wall for years so eventually had to pay for it being taken out and replaced ( by a plumbing firm who didn't fix battens under the chipboard panels they removed for access and left me with creaking first floor panels ).