What type of external wall for a new bathroom?

user1168934

I am in the process of having a small extension done at the back which will be a bathroom + toilet. Initially when I spoke to the builder I told him I would like a double brick wall with insolation in the middle. Now that he has started the work he is saying that having a double brick wall will reqiuire more space and will make the bathroom a bit smaller. He is saying a better idea is to have a single brick wall on the outside and then have some kind of wooden wall with insulation on the inside. He claims that this will save us space and will be as durable and heat efficient as any other wall. I asked him if this will have any moisture related issues since it is a bathroom - he said it won't be a problem because the plasterboards used in the bathroom are moisture resistant anyway.

I have no idea what walls are better. In some unrelated conversations he has been saying that he underestimated the costs in his quote. So it could be that the single wall with wooden wall & insulation is less work and he is just trying to save some cost or he may be right - I simply don't know.

I can insist on the walls being doubel but I have no idea what type is best in this case. Can someone provide some guidance please?

stuart45

What has the Building Inspector said about this?

FreeBear

user1168934 said: Now that he has started the work he is saying that having a double brick wall will reqiuire more space and will make the bathroom a bit smaller. He is saying a better idea is to have a single brick wall on the outside and then have some kind of wooden wall with insulation on the inside. He claims that this will save us space and will be as durable and heat efficient as any other wall. I asked him if this will have any moisture related issues since it is a bathroom - he said it won't be a problem because the plasterboards used in the bathroom are moisture resistant anyway.

Depending on the type of insulation used, you might end up with a thinner wall. But.... Some mortgage providers view timber framing as "non standard construction" which could cause problems when you come to sell.

And frankly, decisions about the type of construction should have been taken during the design and planning phase. Changing construction methods on the fly smacks of a dodgy builder. You do have Building Control involved at all stages of construction don't you.

user1168934

stuart45 said:

What has the Building Inspector said about this?

It has not been discussed with the building inspector yet. This is being built where I had an old brick shed. The inspector just had the first visit where he basically spent 5 minutes looking at the rubble of the existing shed and said he would next like to see how deep the existing foundation is.

user1168934

FreeBear said:

user1168934 said: Now that he has started the work he is saying that having a double brick wall will reqiuire more space and will make the bathroom a bit smaller. He is saying a better idea is to have a single brick wall on the outside and then have some kind of wooden wall with insulation on the inside. He claims that this will save us space and will be as durable and heat efficient as any other wall. I asked him if this will have any moisture related issues since it is a bathroom - he said it won't be a problem because the plasterboards used in the bathroom are moisture resistant anyway.

Depending on the type of insulation used, you might end up with a thinner wall. But.... Some mortgage providers view timber framing as "non standard construction" which could cause problems when you come to sell.

And frankly, decisions about the type of construction should have been taken during the design and planning phase. Changing construction methods on the fly smacks of a dodgy builder. You do have Building Control involved at all stages of construction don't you.

I do have building control involved and I made it very clear to the builder from the start that I need it done properly such that I can get the building reg certificate at the end.

stuart45

Have you got approved plans for the works, or is it being built on a Building notice?

user1168934

stuart45 said:

Have you got approved plans for the works, or is it being built on a Building notice?

It is building notice.

DRP

user1168934 said:

stuart45 said:

What has the Building Inspector said about this?

It has not been discussed with the building inspector yet. This is being built where I had an old brick shed. The inspector just had the first visit where he basically spent 5 minutes looking at the rubble of the existing shed and said he would next like to see how deep the existing foundation is.

This is interesting as I am  planning on building on old foundations myself. What did the inspector need to see? Depth of foundations?

stuart45

In that case timber frame could be used, but as you are the customer it's really down to you.
Personally I would prefer a masonry wall.

molerat

A proper timber frame is no thinner than a double skin masonry wall - outer block, cavity, Sterlingboard sheet, 6" studs, plasterboard.  He likely wants to just stick 2" battens on the wall and board over. Cowboy springs to mind.

user1168934

Cheers folks. I think I will insist on a double masonary wall.