Help with raised patio

[Shona63]

I have a raised patio which has porcelain tiles laid on top and render on the walls. The render as you can see from the photos is cracking and coming away. This started last year and has progressively got worse. Now up 4 years.  I know this is related to water etc but I'm unsure whether it's coming from the slabs and getting behind the render or coming through the walls and into the render.  Any ideas looking at the photos? I know the render needs to come off but I don't want to be in the same situation again in a couple of years so any suggestions on what I can do to stop it happening again would be very much appreciated.
 

[Conor]

Water will be coming through the tiles, down and out through the wall.

 

What's behind the wall and under the patio? Are there drainage channels / slots int he wall?

[Russell griffiths]

You need to clad the walls with something that is not directly fixed to the blockwork like the render is. 
you will NEVER fix the problem without a complete redesign 

the trend of these white rendered walls in a garden situation was always going to fail, everyone is doing them and they will all fail. 

im afraid it’s just a poor design choice. 
 

some form of composite cladding then a larger overhang on the coping stone would have been more robust. 
 

sand it back and paint it, you will need to do this every year, tart it up in the spring, get a summer out of it and let it deteriorate in the winter, repeat next year. 

[Nickfromwales]

Fit and forget.

 

https://www.victorianplumbing.co.uk/casterton-natural-stone-effect-split-face-tiles-100-x-500mm?s_kwcid=AL!15853!3!!!!x!!&gclsrc=aw.ds&gad_source=4&gad_campaignid=20251729566&gbraid=0AAAAAD_SoLZYaExfpwqgPobeUWA1xyGaK&gclid=CjwKCAjw49vEBhAVEiwADnMbbByUNPEnFP30c3GhHEddga3YkEmBorrhHWfYMFRrivJMaE7iQpj74RoCuIgQAvD_BwE

[Shona63]

5 hours ago, Russell griffiths said:

You need to clad the walls with something that is not directly fixed to the blockwork like the render is. 
you will NEVER fix the problem without a complete redesign 

the trend of these white rendered walls in a garden situation was always going to fail, everyone is doing them and they will all fail. 

im afraid it’s just a poor design choice. 
 

some form of composite cladding then a larger overhang on the coping stone would have been more robust. 
 

sand it back and paint it, you will need to do this every year, tart it up in the spring, get a summer out of it and let it deteriorate in the winter, repeat next year. 

I'm not even sure if it's brick or breeze block underneath it. I've had 2 guys out and neither can give me a solution other than rendering and redoing every 3-4 years which isn't an option. Do you think it's coming from the slabs and coming over the edges or through the walls....or both? 

[Shona63]

7 hours ago, Conor said:

Water will be coming through the tiles, down and out through the wall.

 

What's behind the wall and under the patio? Are there drainage channels / slots int he wall?

I don't honestly know what's behind the walls but I'm guessing rubble etc topped with sand of sorts. I know a membrane or similar can be put in the inside but I'm guessing that's not been done. When you say through the tiles do you mean through the grout? If so, is there any type of grout I can use to stop it? Whatever is down just disintegrates when it's brushed. 

[Shona63]

2 hours ago, Nickfromwales said:

Fit and forget.

 

https://www.victorianplumbing.co.uk/casterton-natural-stone-effect-split-face-tiles-100-x-500mm?s_kwcid=AL!15853!3!!!!x!!&gclsrc=aw.ds&gad_source=4&gad_campaignid=20251729566&gbraid=0AAAAAD_SoLZYaExfpwqgPobeUWA1xyGaK&gclid=CjwKCAjw49vEBhAVEiwADnMbbByUNPEnFP30c3GhHEddga3YkEmBorrhHWfYMFRrivJMaE7iQpj74RoCuIgQAvD_BwE

If the water is coming through the walls will it not eventually push the tiles off? 

[Russell griffiths]

4 minutes ago, Shona63 said:

I'm not even sure if it's brick or breeze block underneath it. I've had 2 guys out and neither can give me a solution other than rendering and redoing every 3-4 years which isn't an option. Do you think it's coming from the slabs and coming over the edges or through the walls....or both? 

Both, why does it matter, unless you remove all the slabs on top then dig down the back and waterproof it correctly you are not going to fix it, the best you can do is tart it up and keep it looking fresh. 
 

having it re rendered won’t fix it. 

[Nickfromwales]

1 hour ago, Shona63 said:

If the water is coming through the walls will it not eventually push the tiles off? 

If you hack that off and get it prepped correctly, tile adhesive is cementitious so won’t degrade, so it’ll stay put. 
 

You’d fit cement boards with corrosion resistant screws and dab with same adhesive, and then tile to the boards.

 

Render outside for this kind of thing you see failing everywhere, just look at some walls when you’re driving the ‘burbs and you’ll quickly notice it. 

Edited Saturday at 14:28 by Nickfromwales
Typo

[Brickie]

39 minutes ago, Nickfromwales said:

Render outside for this kind of thing you see failing everywhere, just look at some walls when you’re driving the ‘burbs and you’ll quickly notice it. 

…& my suggestions at work to have engineering bricks to 150mm above g/l is ignored every time

[Spinny]

Maybe consider which way the drainage runs on the patio - is it draining down a slight slope towards the top of the rendered wall ?

It clearly looks worse in line with the grout lines.

Possibly put some sort of waterproof cover over the patio in the winter ?

Possibly drill a hole or three in the render to then measure or assess the level of dampness behind the render/wall and compare with the dampness of the ground at a similar depth elsewhere in the garden. Is it 'filling up' with water behind the wall in the winter with no way to escape.

[Gone West]

We've got a concrete block retaining wall, about 1.5m high, which is unrendered and has drainage holes at the base. I painted it with Durbocem three years ago and it looks the same now as when I painted it. I was thinking of rendering over the Durbocem, to tidy it up, and painting the render, again with Durbocem.

 

https://andrewscoatings.co.uk/shop/interior-exterior-walls/damp-mould/durbocem/

 

 

[Russdl]

It looks like two things going on, it’s got wet at the bottom and soaked it up, as @Brickie says, there should be something other than render for the first 150mm up. The other, and most obvious damage is coming from the water tracking off the slabs down the mortar lines and straight onto the render. You need some kind of drip edge under the slabs to stop the water tracking back to the render (plus the mortar needs to get to the end of the blocks). 
 

it looks like there are some weep vents in the wall, do they weep or are they blocked/just for show?

[Shona63]

3 hours ago, Gone West said:

We've got a concrete block retaining wall, about 1.5m high, which is unrendered and has drainage holes at the base. I painted it with Durbocem three years ago and it looks the same now as when I painted it. I was thinking of rendering over the Durbocem, to tidy it up, and painting the render, again with Durbocem.

 

https://andrewscoatings.co.uk/shop/interior-exterior-walls/damp-mould/durbocem/

 

 

Thank you for this

[Shona63]

5 hours ago, Brickie said:

…& my suggestions at work to have engineering bricks to 150mm above g/l is ignored every time

The builder I used hasn't been the greatest, although recommended. He certainly didn't advise not to do it or explain the consequences, had he I would have looked at other options. 

[Shona63]

6 hours ago, Russell griffiths said:

Both, why does it matter, unless you remove all the slabs on top then dig down the back and waterproof it correctly you are not going to fix it, the best you can do is tart it up and keep it looking fresh. 
 

having it re rendered won’t fix it. 

Expensive option to lift the slabs etc but one which I have  considered but was hoping someone could give me a less expensive option.  

[Shona63]

3 hours ago, Spinny said:

Maybe consider which way the drainage runs on the patio - is it draining down a slight slope towards the top of the rendered wall ?

It clearly looks worse in line with the grout lines.

Possibly put some sort of waterproof cover over the patio in the winter ?

Possibly drill a hole or three in the render to then measure or assess the level of dampness behind the render/wall and compare with the dampness of the ground at a similar depth elsewhere in the garden. Is it 'filling up' with water behind the wall in the winter with no way to escape.

There is a gap at the bottom of the wall before it hits more slabs. I've knocked the walls surrounding the patio and it mostly sounds hollow and unfortunately it's spreading beyond the patio. From what I can gauge the slabs are slightly angled to one corner so the water doesn't lie on top of the slabs.

[Shona63]

5 hours ago, Nickfromwales said:

If you hack that off and get it prepped correctly, tile adhesive is cementitious so won’t degrade, so it’ll stay put. 
 

You’d fit cement boards with corrosion resistant screws and dab with same adhesive, and then tile to the boards.

 

Render outside for this kind of thing you see failing everywhere, just look at some walls when you’re driving the ‘burbs and you’ll quickly notice it. 

Thank you for the advice. I will look into this. 

[Conor]

How long ago was this built?

[Shona63]

9 minutes ago, Conor said:

How long ago was this built?

4 years ago

[Onoff]

Clad with uPVC?

[Nickfromwales]

1 hour ago, Onoff said:

Clad with uPVC?

What? 

 

I'd rather lower my scrotum into an upturned petrol mower than see UPVC installed there.

 

"New balls, please".

 

 

[Onoff]

7 hours ago, Nickfromwales said:

What? 

 

I'd rather lower my scrotum into an upturned petrol mower than see UPVC installed there.

 

"New balls, please".

 

 

 

Wipe clean and hides a multitude of sins, what's not to like!

[Nickfromwales]

1 hour ago, Onoff said:

 

Wipe clean and hides a multitude of sins, what's not to like!

All my work here has been in vain. Upvc cladding is a sin. lol. 

 

”No!”.

[Temp]

I think cladding with something is the way to go. Perhaps fix pressure treated battens on some sort of non rotting stand off and timber cladding. Or that artificial wood made from recycled plastic?