Garden Drainage and Patio area.

Joey the lips · 30-04-2012 8:42pm #1

Hi Folks,

Wondered if i could steal some of your knowledge. I plan to drain my garden which is 40 ft long and 20 ft wide. Its a disaster at the end and it is slowly creaping up the garden. My plan is two fold.

1, I plan to dig a trench in a " W " configuration and bury drainage pipe. I then plan to connect this to a gully trap so silt will gather and on word to the access junction. How deep does this drainage need to be if i am using 4" pipe and how close to the surface do i bring the drainage stone around the pipe

2. Having done this i then plan to create a patio area 12 ft out and 20 ft wide( 1/3rd of the garden) This will hopefully give the kids an area to play on and drain the garden. What dept does the hardcore and sand need to be in a patio area. As the drainge will be under the patio i will need to allow for this as well.

I can provide photos of the garden but tbh its the prity normal builder **** you see everywhere. Compacted no doubt by machinery when the house was built.

ymurtagh · 30-04-2012 10:15pm

The letter " E " would be a lot better, easier and more effecive, with the 18 in deep horizontial feeding the 2ft deep diagonal if you get my drift, keep about 2inch of stone under pipe and 4inch above, no at no point is it less than a foot under ground level, A pipe that is to high covers less of an area and it dries out the area above it too fast in summer, ie. not effective in winter, too effective in summer

Joey the lips · 01-05-2012 8:14am

ymurtagh wrote: »

The letter " E " would be a lot better, easier and more effecive, with the 18 in deep horizontial feeding the 2ft deep diagonal if you get my drift, keep about 2inch of stone under pipe and 4inch above, no at no point is it less than a foot under ground level, A pipe that is to high covers less of an area and it dries out the area above it too fast in summer, ie. not effective in winter, too effective in summer

Actually i get you perfectly. Following on. I would plan to put part of the drainage tube under the patio and the other 2 horizontal lengths in the grass

Bearing in mind the vertical of the " E " would be heading straight down the garden would this have an effect on house foundations if its 18" down.

Again. Thanks for your input as it will now fall perfectly into the gully and allow for branching if necessary.

Joey the lips · 01-05-2012 9:46am

ymurtagh i forgot to ask do you have any idea how deep the hardcore and sand base would need to be for the patio

ymurtagh · 01-05-2012 7:45pm

the foundations will be fine, approx 6in 804 (hardcore), then use a wacker plate and 2in of sand, use wacker plate again, plate cost about 20euro to hire, makes then laying easier too, you could replace the sand with cement is you feeling confident, takes a bit of organising but is a better job in the end

SNAKEDOC · 01-05-2012 10:40pm

you could make your own mix of dust and cement dry and screed it off with some steal pipe keeping your gradient for drainage to a gully then water it in and will set, or cement the outside row in then lay the rest inside on the dust whacked down and pointed with cement. if its your first go at it maybe see if you can ask someone to give you a hand. getting your level right can be tricky and the last thing you want is water to pool at your back door.

Joey the lips · 02-05-2012 8:16am

As i am laying drainage pipes i was thinking of doing a flat paving. ie. no tilt. The paving is only 8 x 4 mtrs so its not to big. I am using alternat size paving so i dont imagine i will get much pooling.

Is my assumption incorrect.

From my research this is the conclusions i have come to.

24" Drainage holes rising to 20" to give a fall
2" of hardcore above and below the 4" pipe
closed the membrane around this 2" and put a further stone on top of it up to the start of the 6" of hardcore. By my estimates this will be 8" of stone up to the hardcore at the deepest point.

Then i put down 6" of hardcore and 2" of sand.

I wash the paving slabs with a brush when finished and seal it all with thompsons water seal.

Anyone any disagreements with this.... Thanks

Lastly I know i will need at least 2 tons of pea gravel for the pipes all over the garden but anyone any estimates of how much hardcore and sand i will need if the patio is 8 mtr x 4 mtrs

Using the sand and hardcore dept above this is what i get

Hardcore
8 mtrs x 4 mtr x 0.15 = 4.8 cubic meters of hardcore.

How many tons is this....?

Sand

8 mtrs by 4 mts x0.05 = 1.6 cubic meters rounded up to 2 cubic meters for pointing.

How many tons is this.

wildlifeboy · 02-05-2012 11:34am

well I got one tonne of hardcore for 11 square metres with a depth of 2 inchs. there are online calculators. google sand/hardcore depth calculator.

I want to jump on your thread if you dont mind for one question. I am also putting this down very soon but I have a shore that is about 10 x 10 inchs and I was told I can get an extension to lift it to the required height for the patio. anyone know what these are called and where i can get them?

Joey the lips · 02-05-2012 12:52pm

wildlifeboy wrote: »

well I got one tonne of hardcore for 11 square metres with a depth of 2 inchs. there are online calculators. google sand/hardcore depth calculator.

I want to jump on your thread if you dont mind for one question. I am also putting this down very soon but I have a shore that is about 10 x 10 inchs and I was told I can get an extension to lift it to the required height for the patio. anyone know what these are called and where i can get them?

Yes you can get an extension. I dont know what they are called but a builders providers will know. Just tell them you want to extend the height of an access junction for paving.

dardevle · 02-05-2012 2:04pm

........

simply called an AJ riser.... just make sure its for the right make - below is typical 'wavin' riser,

images?q=tbn:ANd9GcSuNitKQZ6rkGe2giyINwVHCE3EX6Y7gYfI__05rc566h7yXZxGlA

images?q=tbn:ANd9GcSuNitKQZ6rkGe2giyINwVHCE3EX6Y7gYfI__05rc566h7yXZxGlA

Garden Drainage and Patio area.

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