Water going through gaps in patio ?

Dan-Dan

Hello

Question
On a patio with mortar separating the slabs, is it inevitable that some amount of rainfall, will ingress through the mortar and so, under the slabs

Or is it supposed to be impenetrable?

Thanks

Furts

In practical terms it is inevitable. There will be shrinkage when the mortar pointing is done, paving will settle, frost will get to the mortar ...these all come to mind. Hence there will be cracks - some will not be easily visible because they will be at the joint between the mortar and the paving.

If you consider new home building over the last 30 years there has been no mortar pointing between paving slabs because it is labour intensive and problematic.

Dan-Dan

Furts wrote: »

In practical terms it is inevitable. There will be shrinkage when the mortar pointing is done, paving will settle, frost will get to the mortar ...these all come to mind. Hence there will be cracks - some will not be easily visible because they will be at the joint between the mortar and the paving.

If you consider new home building over the last 30 years there has been no mortar pointing between paving slabs because it is labour intensive and problematic.

Thanks Furts

the water is making a right mess of the mortar and the bricks on the facing wall (its a staggered patio)

Guess ill just have to get the bleach out !

Furts

Dan-Dan wrote: »

Thanks Furts

the water is making a right mess of the mortar and the bricks on the facing wall (its a staggered patio)

Guess ill just have to get the bleach out !

Paving is usually laid on a bed of typically 25mm sand/lime or sand/cement. A porous, weak, mix which is self draining. Do you have this, and if so, can you remove the mortar and allow drainage? Or perhaps replace the mortar with a 3mm single size stone layer?

All paving and patios should be laid to falls, so perhaps yours does not have a fall and is causing you a problem? To assist this fall, which is for drainage, new paving on new buildings is laid with open joints.

I am assuming that you do not have any taps, or rainwater pipes, discharging onto your paving?

Dan-Dan

Hi Furts

We have 2 patios , one is directly outside the house and is approx 6 meters by 8 , it is laid directly on top of a old crazy paving patio , which has the old `french drains` at its furthest point (7/8 meters from the house)

The slabs are laid over the french drains and are 5 lumps of muck under each , there is a fall , but i suspect the water getting through the joints is seeping through the brick work which makes the retaining wall , which then leads downwards to the middle patio

The middle patio was also 5 lumps of muck but had sunk and slabs came loose so the guys came back and relaid onto a slab of concrete instead , which has made it much better

Id like to show a pic to show what i mean , might try to dig one out

p.s no taps of rainwater drains draining onto the slabs

Dan-Dan

please see link
where the plant pot is , the lip , that old wall there , which is original , is becoming filthy with algae , along with the london bricks below it

http://tinypic.com/view.php?pic=2lkxxlf&s=8#.VIG1dTGsWXY

P.s there is a fall

Furts

Dan-Dan wrote: »

please see link
where the plant pot is , the lip , that old wall there , which is original , is becoming filthy with algae , along with the london bricks below it

http://tinypic.com/view.php?pic=2lkxxlf&s=8#.VIG1dTGsWXY

P.s there is a fall

Looking at this, my observations are:
1) London Bricks are notorious for being porous, soaking up moisture, and are unsuitable for use below ground level. Frost is an issue - but you may be in a frost free area. However, the ability to soak up ground water does result in damp and algae - I have it on my home, as do my neighbours.
2) it is also probable that the bricks are absorbing the moisture from the ground behind them. They should have been coated with RIW or similar, if they were to be used here.
3) there should be an adequate overhang on the paving to protect the bricks from surface water. Unfortunately, the recommendation is around 40-45mm which makes the bricks unsuitable for slabs/steps.

One thought is when they are dry, perhaps next summer, is to coat the bricks with Waterseal, or similar. This is a delicate area for there are Forum users who disagree me. Frost can be an issue here, but again this depends where you live and the degree of exposure.

Dan-Dan

Furts wrote: »

Looking at this, my observations are:
1) London Bricks are notorious for being porous, soaking up moisture, and are unsuitable for use below ground level. Frost is an issue - but you may be in a frost free area. However, the ability to soak up ground water does result in damp and algae - I have it on my home, as do my neighbours.
2) it is also probable that the bricks are absorbing the moisture from the ground behind them. They should have been coated with RIW or similar, if they were to be used here.
3) there should be an adequate overhang on the paving to protect the bricks from surface water. Unfortunately, the recommendation is around 40-45mm which makes the bricks unsuitable for slabs/steps.

One thought is when they are dry, perhaps next summer, is to coat the bricks with Waterseal, or similar. This is a delicate area for there are Forum users who disagree me. Frost can be an issue here, but again this depends where you live and the degree of exposure.

Thanks for taking the time Furts

The London Bricks arent under ground level on the top level , or holding ground back , the first wall you can see the top of , is cotswold stone that is the top couple of rows of that original wall.

The bottom retaining wall , which you can see london bricks facing , is concrete blocks almost all the way to the top , say 2 thirds , behind..


All in all Furts , i think i realised a while ago , that our choice of brick , has been our downfall , you can be assured , they dont look like they do in that picture , any more

I see the waterseal arguments on here , my take on it , is possibly i would want the bricks to breathe , if they were holding my house up , but i have no objection to coating bricks such as the ones in our patio , after all , the water behind them will eventually just soak into the ground , one way or other?