Indian sandstone laying newbie

[wertert]

Hi all

I've has a good search and spent time on paving expert so please forgive me asking about this well trodden subject.

I am planning to lay a 90 sqm Indian sandstone patio (riven) over the jubilee weekend. Lots of advice out there but it all seems to differ slightly.

So far all i've done is hire a digger !

The area i am laying on around the house mostly well compacted clay soil. I was going to excavate to a suitable depth and lay the following;

100mm of hardcore. Whack it down.
50mm of MOT type 1 crushed stone. Whack it down.
50 of wet mix bedding for the slabs
22-25mm of Indian sandstone.

whilst excavating I was going to grade the soil away from the house at about 60:1 when follow this up through the layers to give me my run off.

Patio will be foot traffic only.

I need to be very clear about the layer thicknesses as I want the finish floor level to be at a specific height against the house.

I also have to incorporate a few trenches for a low wall and drainage.

flag sizes are
900 x 600mm
600 x 600mm
600 x 300mm
300 x 300mm

laid in a 'random' pattern.

so questions;

- Does the above sound ok ? ie thicknesses of layers etc ?

- should I be asking for any particular spec of hardcore or sub-base ?

- I have seen a number of posts about using a membrane in the layers, assuming this is to stop weed growth.

- Any advice on bedding mix and point would be great.

Thanks in advance.

Wert

 

[WabbitPoo]

I wouldn't bother with the hardcore - a thick woven fabric topped with 100mm whackered crushed stone (20mm to dust is OK) would be fine (unless the clay is very oozy).

Head on over to the garden section regarding mixes.

 

[noseall]

Your base spec sounds good.

When laying slabs avoid 'crossroads' go for 'T' junctions i.e. Do not have four corners of slabs meeting.

Use a screed sand and cement mortar at 5:1. Lay a solid bed and joint the slabs as you go. Do not brush in dry mix if you want the joints to last longer than 12 months. You can produce a nice joint finish with a brickies bucket handle bar jointer.

 

[wertert]

I wouldn't bother with the hardcore - a thick woven fabric topped with 100mm whackered crushed stone (20mm to dust is OK) would be fine (unless the clay is very oozy).

Head on over to the garden section regarding mixes.

ok - i think you're right about the hardcore. Friend of mine gave me the same advice. Makes life easier. Just to clarify, assuming thats 100mm after it's been whackered ?

Any pointers on where I could source the woven fabric ? I've been pointed towards using some kind of geotextile matting.... ?

saying that I found this...
http://www.geotextilemembrane.co.uk/shop/category/39

thanks for the advice.

 

[wertert]

Your base spec sounds good.

When laying slabs avoid 'crossroads' go for 'T' junctions i.e. Do not have four corners of slabs meeting.

Use a screed sand and cement mortar at 5:1. Lay a solid bed and joint the slabs as you go. Do not brush in dry mix if you want the joints to last longer than 12 months. You can produce a nice joint finish with a brickies bucket handle bar jointer.

thanks for the bedding advice.

something like this ? to finish the joints -> http://www.toolstation.com/shop/Han...alltown+Brick+Jointer+12+58/d10/sd2816/p23004

I'm going for the following laying pattern. Reproduced about 6 times. it's alot of sandstone ! Still looking for a good deal

 

[noseall]

Also, avoid any long straight unbroken joints.

Whilst it may look neat and straight on paper, in reality the joint will wander about due to the sizing nature of the different sized slabs.

What you will find is that multiples of smaller units will add up to greater than their equivalent larger unit.

To counter this, you will find that the larger slabs will have bigger joints than the smaller slabs. You should allow for this as you start slabbing otherwise it will mean getting back onto what you have already laid and shoving them around.

 

[wertert]

Hi All

Thanks again for the advice. Todays question is ...

if i'm covering an area 10m x 6m with mot 1 to a whackered depth of 10cm ( as above ) any ideas how many tonne bags of mot 1 i'll need.

thanks

wert

 

[wertert]

Hi All

Thanks again for the advice. Todays question is ...

if i'm covering an area 10m x 6m with mot 1 to a whackered depth of 10cm ( as above ) any ideas how many tonne bags of mot 1 i'll need.

thanks

wert

Answering my own question.....

take the sqm ie 60. x by 0.1 to give m2. Now x 1.85 to give tonnes required 11.1 tonnes. so alot then....

 

[WabbitPoo]

Not quite that much in practice. But yes, quite a lot. See if you can get "crusher run" delivered with your skip - much cheaper from skip companies than from BMs. Mine delivers it in a skip, tips it out for me. Even though you still have to shift it, its a lot easier to shovel it off the drive than out of those damn bags