I WANT TO LAY A NEW PATIO OVER EXISTING CONCRETE

[ladypickers]

Can I lay a new pation over existing concrete, what the best way to do it I would like to use paving slabs but wonder what sort of bed I should use for the slabs, as we live in an end of terrace victorian house there is concrete all the way round the sides and back so it would mean the slabs would but up to our fence and the wall of the house plus some flower beds. Would it be sensible to lay the slabs so as to leave a 3-4 inch gap at the edges of the laid areas and fill with shingle so as not to breach any DPC etc and to give a run off. We also have a problem where the existing patio falls away slightly meaning water collects at one end. Ideally i dont want to be putting in loads of drainage as we plan to sell the house and are just looking to tidy it up. Any advice would be really appreciated. Also can anyone recommend any good suppliers for reasonably priced paving....apoligies to the moderators if this request is not allowed please edit accordingly

 

[nstreet]

At what distance is the current concrete below the dpc?

OK, so you don't put in any drainage, the people that want to buy your property turn up on a very wet day and see the pooling of water at the end of the patio, how will you explain this away? you will more than likely have to reduce the price.

Why not put a low level wooden deck on the concrete. It will be cheap to put down and make the area less unsightly, the only drainage problems will be your existing ones, but they will be under the deck and not as easy to see, not that you should try and hide problem.

 

[Dewy]

The top of any patio should be 2 bricks (6") below the dpc.
If you make sure the slabs start at this level then run away from the house slightly you should have no water problems.
You may find you need a place at the lowest part with gravel sunk into the soil to allow drainage.
The reason for the 2 bricks (6") below dpc is so that rain splashing off the path or patio wont gain entry.

 

[ladypickers]

thanks for the replies, DPC is well above patio, more concerned with the best way to lay this, what to use and do I lay over the existing concrete

 

[Thermo]

if youre laying on the concrete youll need a fairly wet bed to ensure it bonds to the concrete and that you dont get any movement later on. Also give the concrete a wash over with a slurry of wet neat cement or pva to help bond it

 

[loublou]

sounds like the new patio won't be going anywhere but upwards!

All the hard work of putting down a decent base is done for you.

 

[WabbitPoo]

The top of any patio should be 2 bricks (6") below the dpc.
If you make sure the slabs start at this level then run away from the house slightly you should have no water problems.
You may find you need a place at the lowest part with gravel sunk into the soil to allow drainage.
The reason for the 2 bricks (6") below dpc is so that rain splashing off the path or patio wont gain entry.

I've never understood this requirement - water splashing onto brickwork from a patio is the same as water splashing from the sky - ie rain. I always lay patios at this 6" below dpc level, but have never agreed with the basic principle!

 

[masona]

I've never understood this requirement - water splashing onto brickwork from a patio is the same as water splashing from the sky - ie rain. I always lay patios at this 6" below dpc level, but have never agreed with the basic principle!

Because if it's any less than 150mm you will get continuity of rain above the dpc giving you damp problem. The rain above the wall run down it instead of driven into the wall.

 

[WabbitPoo]

I've never understood this requirement - water splashing onto brickwork from a patio is the same as water splashing from the sky - ie rain. I always lay patios at this 6" below dpc level, but have never agreed with the basic principle!

Because if it's any less than 150mm you will get continuity of rain above the dpc giving you damp problem. The rain above the wall run down it instead of driven into the wall.

I still don't see the difference - rain/splashback.......

A lot of customers want decks to be flush-ish with the internal floor level, making egress simpler. I see a lot of decks laid that way.....

 

[Damocles]

Building inspector man he say.....
You did know that a patio is required to conform to building regulations?

I think it is probably just a belt and braces approach. But you should think about the possibility that the damp course might not be in very good nick. Then those two layers of brick are helping to reduce the amount of damp getting above it.

 

[Slugbabydotcom]

I still don't see the difference - rain/splashback.......

Dont forget that you have water dripping from window sills which has run from the impervious window, overflow pipes, pressure relief pipes from sealed boiler systems, leaking soil and waste pipes and gutters also cause water concentrations in the 'splashback' zone which do not dry up as easily as rainwater.