Porcelain Coping Stones for Parapet Wall

[steveoelliott]

Hi Folks,

 

Just wondering what the pros and cons are for using porcelain coping stones on a parapet wall over standard concrete ones... Obviously porcelain is non porous so that's a big plus. Just wondered if they would be considered suitable? I can't see any reason why not.

https://www.castlecomposites.co.uk/product/porcelain-coping-stones/

 

One concern I do have is whilst they feature a drip detail, they are not weathered and thus flat. Also much thinner than concrete copings.

 

Thanks...

[nod]

Porcelain would be fine 

I wouldn’t rely on a capping to seal the parapet 

I fixed ply on the top of the parapet and returned the fiberglass over the top of the ply and the stone coping just became decretive

If yours is more like a balcony with brickwork showing 

You can do the same with a 50 mil lap and trim 

 

[steveoelliott]

Thanks... Yes mine is a roof terrace.

 

So on one of my walls that's exactly the intention, to have the roof membrane up and under the copings. The other wall is a lot higher and it would look nasty having the membrane run all the way up so intend to use a DPC under the capping on that one.

[AliG]

Seems like a good idea. We have a lot of stone coping stones and they soak up too much water, I need to seal them this year when it dries up.

 

What I do notice is that water tends to run through the joints, so even if the porcelain is not porous you need to watch for what happens at the joints.

 

One tip for a roof terrace. We have a small area and the slabs on the terrace are set off the bassoon plastic feet to be level with the door that opens onto the terrace. The problem with this is they are set higher than the membrane and so water splashes onto the render on the walls.

 

Thus if doing this I would recommend that the membrane runs to above the height of any surface on the terrace.

Edited March 9, 2021 by AliG

[steveoelliott]

22 hours ago, AliG said:

Seems like a good idea. We have a lot of stone coping stones and they soak up too much water, I need to seal them this year when it dries up.

 

What I do notice is that water tends to run through the joints, so even if the porcelain is not porous you need to watch for what happens at the joints.

 

One tip for a roof terrace. We have a small area and the slabs on the terrace are set off the bassoon plastic feet to be level with the door that opens onto the terrace. The problem with this is they are set higher than the membrane and so water splashes onto the render on the walls.

 

Thus if doing this I would recommend that the membrane runs to above the height of any surface on the terrace.

 

Yes, I would keep an eye on the joints following and also on one of the walls run the membrane up and under the coping. For the higher wall a DPC will be installed under the copings so in theory failure of the mortar joints shouldn't let water ingress.

 

Noted and agreed on running the membrane up higher... That is the intention on all areas besides the one where the membrane will run full height.

[steveoelliott]

On 08/03/2021 at 16:55, nod said:

Porcelain would be fine 

I wouldn’t rely on a capping to seal the parapet 

I fixed ply on the top of the parapet and returned the fiberglass over the top of the ply and the stone coping just became decretive

If yours is more like a balcony with brickwork showing 

You can do the same with a 50 mil lap and trim 

 

 

 

 

So no concerns with the thickness or them being flat on a parapet wall? Unfortunately they don't do once weathered. My theory is that with membrane up and under copings on one side and a DPC in place on the other extending 5mm past brickwork, as in your case if the copings do let some water through, it shouldn't have anywhere to go.

 

The below gives you a visual of what is in place currently... It leaks!

 

The old copings are being removed and replaced with the flat porcelain ones. The roof membrane is being replaced and taken up and under the lower parapet wall. The higher parapet wall would look horrendous if we were to take the membrane up and under so a DPC protruding 5mm either side will hopefully suffice. Lead saddles to be used at abutments (none in place currently)

 

Membrane to run up higher than it does at present on other walls.

 

Edited March 23, 2021 by steveoelliott