Renovations - Running 32mm basin waste pipe in load bearing wall

TranceNRG

Hi guys,
I'm after a bit advice. I recently bought a 2 bed ground floor (period conversion) flat in West London and started a full refurbishment about a month ago. My builders are about to the do bathroom now so I have been looking at various bathroom fittings. I would like to have a wall hung vanity basin unit but the problem is currently the waste pipes and copper water pipes are outside the wall (they were hidden with a box previously) and I'd like to have these pipes in the wall and make it look clean.

The bathroom is in an extension to the building. The toilet and basin are on the load bearing structural wall. I believe the thickness of the brick wall is about 20-25cm. To hide the pipes in the wall they'll have to run them horizontally about 1.2m.

Here's the layout:



So the toilet and basin will be on the right hand side of the toilet.

My builder was intially reluctant to run the pipes in the wall but finally agreed to channel them in the wall after he realised that it's a double brick wall (also after my nagging .

I had a mate of mine (who's a carpenter/joiner by trade) come to the flat last night and I told him about my dilemma and running the waste pipe and copper pipes in the wall and he reckons it's not good practice and it's better to have them boxed in.

I've read various forums about this and it seems some people are saying as long as the diameter of the drilled hole is not too big (some were saying less than 1/4 of the thickness of the wall, some were saying less than 1/6th of the thickness of the wall and some were saying less than 40% of the thickeness of the wall) then it's not a problem and shouldn't really weaken the supporting wall.

What are your thoughts on this? Can we hide the pipes in the wall without weakening the wall? Any drawbacks of doing this? My builder did say that if the pipes are in the wall and there's a leak, it's worse than in a boxed in solution.

Thanks.

BigBopper

Your builder, your mate and various other forums said its not a good idea. So you post on here looking for the answer you want.

It'll be fine to do it.

TranceNRG

As I sad there were various answers on various forums. I want to know what's legally allowed. I suspect my builder initially said it because it's more work for him.

Rain_Shadow

Any chance of reposting that picture so it doesn't stretch from here to the other side of my room?

TranceNRG

Rain_Shadow wrote: »

Any chance of reposting that picture so it doesn't stretch from here to other side of my room?

??? It's not a big picture at all. Not sure what's causing it to expand on your screen but are you not able to get a picture from what I described?

Doozergirl

TranceNRG wrote: »

As I sad there were various answers on various forums. I want t you o know what's legally allowed. I suspect my builder initially said it because it's more work for him.

!!

It isn't good practice at all. Of course you are weakening the wall. Chasing into the wall should always be kept to an absolute minimum and horizontally is many times worse than vertical.

Essentially, you weaken the whole wall to its weakest points. Affecting the structural integrity of a wall for reasons of vanity is ridiculous.

You either plan the room so that wastes can go straight out of an external wall, or you use cabinetry to hide it (like in a kitchen) , or you build out a false stud wall to hide it, or you box it in.

You might push your builder into doing it but it is an absolute bodge.

andyhop

Pretty much all of our bathroom refurbs are stripped right back due to the old plasters not being able to take the weight of modern day tiles.

Often we would remove 15-20mm of the face brick, Dot and dab plasterboard to achieve a flat and stable substrate then cut the pipe work into plasterboard/ removed face brick

The depth will be enough for 32mm solvent weld, often oversized to 40mm to ensure good flow

Remember any copper pipe work should be wrapped in Denso tape /duct tape as the lime in the cement will eat into the copper over a period of time