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Posted: Mon Apr 03, 2006 8:19 pm
by simon(Newcastle)
I just cant seem to get my head around how to set a fall for a patio that is up against a house. From what i can gather there seems to be two methods:
1) use leveling pegs 6ft apart, putting a straight edge across and placing a 1inch block under one peg for the desired fall
2) make the ground itself slope away from the house(by digging out), then knock in your leveling pegs for the disired fall.
If i was to use method 1 surerly you would have different depths for your subbase as you are knocking the pegs into the ground 1 inch over 6 foot (is this right?)
please help (me heads in bits)
Posted: Wed Apr 05, 2006 1:04 pm
by paulcurrie1
Hi Simon,
I have a similar problem with my patio - Its about 9 foot deep up against my house - just wondering who told you to give a fall of 1 inch per 6 feet - is this the right amount?
I was just planning on using builders string from one peg next to the house, then lead it to another peg 9 foot away by the lawn, and ensure that the 2nd peg is lower than the first!
Paul
Posted: Wed Apr 05, 2006 2:28 pm
by simon(Newcastle)
hi paul,
i got the info out of a garden diy book and there is also info on this site in relation to setting falls, but 1cm in a metre (or 1in/6ft) seems an adequate fall for a patio.
Your method seems ok but the best bet is for someone with more knoledge (ie someone on this site) to advise you or US on the correct procedures!!)
Posted: Wed Apr 05, 2006 6:13 pm
by Tony McC
Firstly, 1cm per metre is NOT adequate for a patio. That's only 1:100 which will result in ponding, and with certain types of paving, very definite puddles. 1 olde-worlde inch in 6 of ye olde feete is verily 1:72, which is a not more realistic, but still not quite enough. For riven flags (real or concrete) aim for 1:60 as a minimum.
How the fall is created depends on the job itself. Ideally, we'd create the fall while excavating to formation level, as this would give a sub-base (assuming one is being used) of regular, uniform depth, but it's not always feasible to work this way. F'rinstrance: you wouldn't always create fall at formation level for an elevated pavement (there are always some exceptions).
Assuming this patio is a typical installation, with nowt out of the ordinary, then the fall would be created at formation level. If this patio was, say, 3 metres wide, we'd need at least 1:60 fall (17mm per linear metre) so that means the "outer" edge would need to be at least 51mm lower than the house edge.
So, at one end of the patio, a peg or pin would be knocked in at 3m from the house, and the level transferred using a straightedge and spirit level. The same happens at the far end of the patio and then a string line is stretched tight between the two pins so as to create a level guide. None of this stupid nonsense of knocking in wooden pegs every half metre or so - no real contractor does that! A simple taut string line on the outside edge and then a decent straightedge that is long enough to span from house to outside edge to assess level and depth.
Posted: Thu Apr 06, 2006 1:17 pm
by paulcurrie1
Thanks Tony, that is really usefull information.
Brilliant website aswell - well done!