Copper Pipes in New Build

[adh]

Hi All,

Our plumber is about half way through our first fix on a new build house. He's using copper throughout and need some advice on covering the copper pipes before plasterboarding. Some of the pipes come down the internal block walls to the sanitary fittings etc. At present these are simply surface clipped using plastic nail clips. We are having dot & dab plasterboard finish over the block work walls. Do we need to cover the copper pipes with anything before plasterboarding over? I've heard some people use Denso tape. Is it necessary as our plumber wasn't going to cover them.

Many Thanks.

 

[andyg0507]

if the board adhesive makes contact with the copper this can corrode it very quickly, denso tape is an option, in the past we have run plastic where things are to boarded so this corrosion doesnt happen.

hope this helps.

 

[adh]

if the board adhesive makes contact with the copper this can corrode it very quickly, denso tape is an option, in the past we have run plastic where things are to boarded so this corrosion doesnt happen.

hope this helps.

Thanks for that. Our plumber was against using plastic but I can see the logic in this instance. I've also looked at flashing tape instead of Denso as that stuff is awful to work with.

Any potential issues with using flashing tape as opposed to anything else?

 

[andyg0507]

personaly i would stick with the denso tape, but what you have got to bear in mind is that once your walls have been boarded there is no way of getting to them if theres a leak.

 

[Blackcatgas]

Tubular hair felt lagging, if you cant get tubular then use normal hairfelt on a roll and fold it over the pipe, it will also acomodate any expansion and contraction as the copper pipe heats up, you really dont want to be putting bare copper between breeze and plaster board, gas pipe wants covering in yellow pvc tape.
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[adh]

Tubular hair felt lagging, if you cant get tubular then use normal hairfelt on a roll and fold it over the pipe, it will also acomodate any expansion and contraction as the copper pipe heats up, you really dont want to be putting bare copper between breeze and plaster board, gas pipe wants covering in yellow pvc tape.
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Thanks for the info. I've seen that used before. However will it act as a suitable barrier against bonding compound as it will allow moisture to pass?

 

[oldplumber]

cannt see why you dont just specify using plastic coated pipe thats designed to be used in this situation, and just denso any joints. using tubular felt, electricians tape isnt a recignised method of protecting cu tube, building regs would not pass it if the inspector knows their stuff.

 

[adh]

cannt see why you dont just specify using plastic coated pipe thats designed to be used in this situation, and just denso any joints. using tubular felt, electricians tape isnt a recignised method of protecting cu tube, building regs would not pass it if the inspector knows their stuff.

Afraid building inspector not interested and neither is NHBC. Have it in writing from both that no protection required. They said it doesn't come under their remit.

Have looked at the water regulations and only stipulation is that pipes buried in a chase are wound with impermeable tape.

 

[oldplumber]

Afraid building inspector not interested and neither is NHBC. Have it in writing from both that no protection required. They said it doesn't come under their remit.

Have looked at the water regulations and only stipulation is that pipes buried in a chase are wound with impermeable tape.

which is why nhbc is such a waste of money and proves that the buildings inspectors have lost the bubble years ago. dont forget your paying the bills, if you stipulate you want it done in a particular manner expect your plumber to do it. it wont cost much more than normal cu tube, approach your guy gently plumbers can be techy and sarcastic at the best of times.🙂

 

[adh]

which is why nhbc is such a waste of money and proves that the buildings inspectors have lost the bubble years ago. dont forget your paying the bills, if you stipulate you want it done in a particular manner expect your plumber to do it. it wont cost much more than normal cu tube, approach your guy gently plumbers can be techy and sarcastic at the best of times.🙂

Couldn't agree more! The whole system is a disgrace and we pay for it. Having been through a lot with building control and NHBC I have very little faith in them to do what's right.

I shall have a quiet word with my plumber!

 

[Blackcatgas]

Thanks for the info. I've seen that used before. However will it act as a suitable barrier against bonding compound as it will allow moisture to pass?

Yes it will allow a little moisture to pass, this moisture then dries out as the compound sets, this is the way copper pipe has been laid in walls in millions of buildings for the last 80+ years. the copper pipe in the walls will out last you.

 

[REDSAW]

i am a bit more curious with your o.p.

is it you doubting the plumber or the plumber really dosnt know how to protect the pipe???????

 

[adh]

i am a bit more curious with your o.p.

is it you doubting the plumber or the plumber really dosnt know how to protect the pipe???????

On the whole, I'm very pleased with how he works. Our setup is rather more complex than the usual so finding someone who was able to work on this project was not easy. However I was concerned that he wasn't going to protect the pipework behind the plasterboard as I knew the potential pitfalls of bonding compound on copper. I have since spoken with the building inspector, NHBC and a large local building contractor, who I know well, and none of them thought it necessary to protect the copper pipework. They said that although bonding compound could damage copper, it wasn't anywhere near as corrosive as cement screed and that a good plasterer would not get compound on the copper in the first place!

It's not a matter of him not knowing how to protect the pipe, it's just that he doesn't normally do it! This guy is no rogue tradesmen either as I spent a long time researching before choosing a plumber and he came highly recommended. As I've said I'm very pleased with his work it's just this one aspect I was concerned about. However if I took the advice of the official local building inspector and NHBC, I wouldn't be doing anything. However as it's my home for the foreseeable future, I do not want problems in 10 years time!

Incidentally I have the water regulations guide and the only reference to this I can find in Schedule 2 where regulation G7 states that 'pipes bedded in chase on an internal wall to be wrapped in impermeable tape' - this was from diagram G7.1k.

Just as an update, I received the following from NHBC this afternoon. This came from their technical standards department:

There is nothing to say that drywall adhesive is corrosive to metal pipework and a quick call to British Gypsum also confirmed that they did not think is would be a significant issue - However it could be an issue in relation to temperature movement - it is not recommended to embed pipes in because of this.
*
NHBC's position is that on the grounds of manufacturers requirements you should not bond over pipes if it is avoidable. However there are no additional provisions required where this might occur.

 

[oldplumber]

Yes it will allow a little moisture to pass, this moisture then dries out as the compound sets, this is the way copper pipe has been laid in walls in millions of buildings for the last 80+ years. the copper pipe in the walls will out last you.

copper pipe from 50 years ago had nice thick walls, the tinfoil thick tube we use no isnt so good at avoiding pinholing, if it meets a corrosive agent

 

[Blackcatgas]

copper pipe from 50 years ago had nice thick walls, the tinfoil thick tube we use no isnt so good at avoiding pinholing, if it meets a corrosive agent

Table x copper has been around for 40+yrs, plaster board and adhesive since before i was born, 100000s of homes have had copper pipe installed in hair felt lagging behind plasterboard and even wet plaster with no ill effect and is still how it is installed today. the cost of plastic coated copper is very high, denso tape is horrible stuff, if thats how you install pipes behind /in plaster etc then fair play to you, il keep on doing it how I have for the last 15yrs and my mentors have for the last x amount of years.😀

 

[oldplumber]

never said that how i do it, just what all the books quote, and what my exam questions were anwered with a while back.

 

[REDSAW]

i thought the plasterer is going to dot n dab plasterboard on, not skim over the pipes?....
if not then tell the plasterer to steer clear of them with the gobbo/.
i have never had any probs before 20 years on pipes plastered over, now we usually run plastic thru clipid well with no joints behind but whatever the method its all down to 'how much'.
a cheap good idea is to run it through 22mm plastic o/f pipe. and by the way, denso leaves staining in plaster and may permiate thru p/board.

 

[adh]

i thought the plasterer is going to dot n dab plasterboard on, not skim over the pipes?....
if not then tell the plasterer to steer clear of them with the gobbo/.
i have never had any probs before 20 years on pipes plastered over, now we usually run plastic thru clipid well with no joints behind but whatever the method its all down to 'how much'.
a cheap good idea is to run it through 22mm plastic o/f pipe. and by the way, denso leaves staining in plaster and may permiate thru p/board.

It will be dot & dab. It was the bonding compound used to secure the plasterboard which I had read was corrosive to copper. It turns out this is not the case, or at least not from what I have been told from NHBC.

I will ensure they do not put compound directly over the copper and will use a barrier tape to protect them as a backup.

Thanks for the comments.