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Posted: Mon Sep 12, 2011 8:15 am
by Skates
Hi,
We're laying a patio in our garden and are struggling a bit with levels and drainage - can someone help??
We've built a summer house in the corner of our garden and surrounded it with decking. The plan is to build a patio around the decking which will lead up to our lawn. The issue we have is that the lawn is very slightly higher than the decking, meaning that if we lay the patio as it is, the water will run back towards to the decking.
We've been thinking of a few options but none of them are ideal...
1 - put in an aco drain between the patio and the decking, so the patio slopes towards the decking and the drain will remove the water
2 - somehow make the lawn lower - is this even possible? so that the patio can slope towards the lawn to remove the water. (taking into account that the patio will be approx 4m long and the lawn is only an inch or so higher so the levels are only very slightly out)
3 - make the patio slope towards the lawn and put in a step with a drain in it. so you are stepping from the lawn down onto the patio.
Does anyone have any advice for which is the best option or if there is something else we haven't considered? all thoughts welcome!
Thanks
Katie
Posted: Mon Sep 12, 2011 8:38 am
by Carberry
Is there anything under the decking? a membrane and some pea gravel on top of it? If there is then just let the water go under the decking.
1. Could do
2. You can make the lawn lower, if you want to keep the lawn then you have would have to get a turf cutter, take a skimming off the soil with a lawn lute or digging it out and raking over then relaying turf. Will need to be done within 24 hours so you don't kill off your turf. If you went to all that trouble though you are just as well buying new turf.
3. I get the impression that this wouldn't work or look right.
Posted: Mon Sep 12, 2011 11:57 am
by Skates
so underneath the decking and summer house is a concrete base with wooden joists running across the top of it. The summer house and decking are secured to the joists.
Do you mean leave a small gap between the decking and the patio so the water just runs between the gap rather than onto the decking? I think we need to leave a little gap anyway in case the decking expands...
Thanks
Posted: Mon Sep 12, 2011 1:45 pm
by Carberry
Skates wrote:so underneath the decking and summer house is a concrete base with wooden joists running across the top of it. The summer house and decking are secured to the joists.
Do you mean leave a small gap between the decking and the patio so the water just runs between the gap rather than onto the decking? I think we need to leave a little gap anyway in case the decking expands...
Thanks
Where does the water run on the concrete base? Or would it puddle against the joists?
You normally have 6mm spacing between decking boards.
Posted: Mon Sep 12, 2011 3:15 pm
by Skates
The concrete base is angled so that the water which landed into between the gaps on the decking would run down the concrete slabs, in parallel to the joists, to a lower soil area at the back of summerhouse.
If we were to just leave a further 6mm gap between the decking and the patio then I'm assuming the water would just drain down in the same way - as the concrete base comes out a few inches further than the decking.
When you cement / mortar inbetween the patio slabs, how would go about doing this next to the decking to ensure there is a gap. Or would you just start the slabs 6mm away from the decking and not cement / mortar that side?
Hope this makes sense!
Thanks
Posted: Mon Sep 12, 2011 3:32 pm
by Carberry
Right now it is a choice between a drain in between decking and patio or letting water drain underneath decking. If the drainage is adequate underneath the decking then I would just let the patio drain there.
I would start the slabs away from the decking with the edge slabs laid on a bed of concrete so they went nowhere. I would go with a slightly larger gap, maybe 10mm. The 6mm gap in decking is to allow for any swelling of the wood when they're wet.
Bear in mind that all this is without actually seeing the site or any plans.
You also need to consider how much more difficult it will make cutting the grass, if you get it wrong then you will need to cut it near the patio with a strimmer. If you get it right then you can just run over it with the lawnmower,.
Posted: Mon Sep 12, 2011 4:28 pm
by Skates
Cool, I'll go home and have a look at the drainage and check with a level tonight. thanks so much for your help!
Posted: Mon Sep 12, 2011 5:55 pm
by lutonlagerlout
this sounds like a very simple to solve problem for the right person
if everything falls away from the main house I cannot see any issues
the grass needs to be cut out and level reduced for the slabs anyway,just lay your slabs to a string line
LLL 
Posted: Tue Sep 13, 2011 8:01 am
by Skates
Hey,
sorry what do you mean the grass needs to be cut and layer reduced for the slabs anyway? Do you mean because it's an inch higher than the patio it needs to be reduced by that amount, or for some other reason?
Thanks