New Patio

[HJB]

Hi

I am having a new patio installed and have a couple questions.

The guys that are doing it are removing some existing turf to extend out and lift the old patio. However they said they can just put type 1 over the existing sand that was under the patio, then on top of the type1 it will be the sand/cement mix for sandstone.

Is this correct or should the old sand be removed also?

Regarding drainage I had asked a drainage grid be put in along the sleeper edge on the far side of the patio where the grass is (grass, then a sleeper height drop to the patio), but they are saying the way it will need to be laid, they would be best running the drainage grid along the house side of the patio. I have always read dont run these along side of house. The pipe is getting tided into the rain water downpipe for info.

Any advice on this?

See attached Photos purple lines are the drainage grid, on both options... the 2.4m line is a step down from house. The Red line is Sleeper side where grass is.

[Marvin]

Hi @HJB

 

If the old patio was stable then type 1 on the existing sand seems OK to me. However I would want the old sand compacted before the type 1.

 

I would want to have the grass removed where the patio is to be extended and dig down to the same level as the bottom of the sand used on the existing patio, again assuming old patio was stable, and compact the type 1 bringing it up to the new level.

 

Surely you want the rain water to fall away from your building? So drain run between patio and grass...

 

Good luck

 

Marvin

[HJB]

The patio was sinking and uneven which is why I wanted this dug out. It wasnt whacked prior to typ1, the type 1 was put on top then whacked.

 

The grass was removed and leveled to the old sand.

 

The original request was to have the drain along the sleeper and then run house to sleeper (grass side), but as they havnt dug down, they now said on day 2 the run has to point towards the house and drain needs to be move the that side.

Edited November 10, 2021 by HJB

[Roundtuit]

If the old patio was dodgy, I'd want at least 100mm of type 1 compacted. Are they raising the height of the patio to avoid digging down?  As above, the fall on the patio should run away from the house, so the drain needs to go where gravity dictates if the water can't soak away into the ground.  Sounds like they don't much like digging.

[Marvin]

The web site pavingexpert.com is an excellent source of information.

 

Do you have details of the type of sandstone being used? 

[HJB]

There is 100mm of type 1 been laid and whacked also. I just thought it would have been best to removed the old sand then put type 1 down.

 

the patio will be raised for this very reason, they removed the old slabs but not anything else underneath so by the time you put on 100mm type1, whatever the sand/cement mix is and the height of the sandstone must be out 150-200mm higher that the previous one.

 

I am thinking of telling them to put a drain in where the sleeper is, (the original request) and have a slight ridge so water will run off to both, so it’s not all heading towards the house. I think this will do the trick, not ideal as didn’t want 2 channel drains on show but if it helps water flow then it’s the best option.

 

see attached 

[HJB]

1 hour ago, Marvin said:

The web site pavingexpert.com is an excellent source of information.

 

Do you have details of the type of sandstone being used? 

 It’s this or very similar Natural paving classic stone.

[Marvin]

Putting a ridge in the patio seems to me to be complicating things...

[HJB]

Its the only way I thought to get the fall to both side, maybe it can be done without a ridge and laid a certain way to do this.  I dunno but there needs to be something along that sleeper so not everything is pointing to the house.