Hi

I am looking to put down a new paved patio in my garden. This is
approx 12m2 and will only get light use. I have come across some
conflicting advice regarding what to use as a sub-base.

Some advise that for a low traffic area 50mm of sharp sand will
suffice.

Some advise that 75mm of foundation is required beneath the sand. Of
these some say to use aggregate alone, some say to use a mix of
aggregate and cement.

So my questions are, is an aggregate foundation necessary, and if so
should cement be included? Also, should the sharp sand be mixed with
cement?

Cheers, Adam

I am looking to put down a new paved patio in my garden. This is
approx 12m2 and will only get light use. I have come across some
conflicting advice regarding what to use as a sub-base.

http://www.pavingexpert.com/patio01.htm

Christian.

Adam-the-Kiwi wrote:
Hi

I am looking to put down a new paved patio in my garden. This is
approx 12m2 and will only get light use. I have come across some
conflicting advice regarding what to use as a sub-base.

Some advise that for a low traffic area 50mm of sharp sand will
suffice.

Some advise that 75mm of foundation is required beneath the sand. Of
these some say to use aggregate alone, some say to use a mix of
aggregate and cement.

So my questions are, is an aggregate foundation necessary, and if so
should cement be included? Also, should the sharp sand be mixed with
cement?

Cheers, Adam

A lot depends on what is underneath soil wise.

If clay, use a pretty fair base of rubble, limestone or what have you,
because it shrinks in summer alarmingly.

Personally I then laid on a very WET later of sand and cement - sharp
sand - because I was laying unequal thickness sandstone. I needed to
tamp each one down.

If you are using machine made slabs, a dry mix laid flat first is a lot
quicker.

The theory behind the cement is that it stabilises the sand which won't
then wash away.

The Natural Philosopher wrote:
Adam-the-Kiwi wrote:
Hi

I am looking to put down a new paved patio in my garden. This is
approx 12m2 and will only get light use. I have come across some
conflicting advice regarding what to use as a sub-base.

Some advise that for a low traffic area 50mm of sharp sand will
suffice.

Some advise that 75mm of foundation is required beneath the sand. Of
these some say to use aggregate alone, some say to use a mix of
aggregate and cement.

So my questions are, is an aggregate foundation necessary, and if so
should cement be included? Also, should the sharp sand be mixed with
cement?

Cheers, Adam

A lot depends on what is underneath soil wise.

If clay, use a pretty fair base of rubble, limestone or what have you,
because it shrinks in summer alarmingly.

Personally I then laid on a very WET later of sand and cement - sharp
sand - because I was laying unequal thickness sandstone. I needed to
tamp each one down.

If you are using machine made slabs, a dry mix laid flat first is a lot
quicker.

The theory behind the cement is that it stabilises the sand which won't
then wash away.



Or get redistributed by ants

"Stuart Noble" wrote in message
...
The Natural Philosopher wrote:
Adam-the-Kiwi wrote:
Hi

I am looking to put down a new paved patio in my garden. This is
approx 12m2 and will only get light use. I have come across some
conflicting advice regarding what to use as a sub-base.

Some advise that for a low traffic area 50mm of sharp sand will
suffice.

Some advise that 75mm of foundation is required beneath the sand. Of
these some say to use aggregate alone, some say to use a mix of
aggregate and cement.

So my questions are, is an aggregate foundation necessary, and if so
should cement be included? Also, should the sharp sand be mixed with
cement?

Cheers, Adam

A lot depends on what is underneath soil wise.

If clay, use a pretty fair base of rubble, limestone or what have you,
because it shrinks in summer alarmingly.

Personally I then laid on a very WET later of sand and cement - sharp
sand - because I was laying unequal thickness sandstone. I needed to tamp
each one down.

If you are using machine made slabs, a dry mix laid flat first is a lot
quicker.

The theory behind the cement is that it stabilises the sand which won't
then wash away.



Or get redistributed by ants

Indeed: it is wise to contain the sand at the edges by either kerbstones of
some sort, or as I did with my patio, concrete.

Actually I used a 3" concrete foundation on 2" or so of sand, so all I did
at the edges was use 6" of concrete to keep the sand in. The advantage of a
concrete bed is that the slabs don't crack/settle over time and you don't
get weeds either.

If you go for sand alone, do use a geotextile sandwiched between two layers
of sand to discourage the weeds.

Andy.

Adam-the-Kiwi wrote:
Hi

I am looking to put down a new paved patio in my garden. This is
approx 12m2 and will only get light use. I have come across some
conflicting advice regarding what to use as a sub-base.

This all depends on what is there now, it cannot be answered until it is
known.

Some advise that for a low traffic area 50mm of sharp sand will
suffice.

Some advise that 75mm of foundation is required beneath the sand. Of
these some say to use aggregate alone, some say to use a mix of
aggregate and cement.

So my questions are, is an aggregate foundation necessary, and if so
should cement be included? Also, should the sharp sand be mixed with
cement?

Cheers, Adam

If the land to be paved is already covered with concrete / tarmac / paving,
then 50mm of dry sand and cement is adequate, if it's loose soil in
flowerbeds, then this is going to sink, so it needs to come out now and
filled with crush and run, likewise if you are removing a section of
lawn...if the ground is firm, use S&C, if not use hard core first, then S&C.

The easiest way to get it right is to trammel it with a dry mix, then lay
each flag gently down flat on it and giveit a few taps in the centre to bed
it in, don't walk on any til the next day.

"Adam-the-Kiwi" wrote:
Hi

I am looking to put down a new paved patio in my garden. This is
approx 12m2 and will only get light use. I have come across some
conflicting advice regarding what to use as a sub-base.

Some advise that for a low traffic area 50mm of sharp sand will
suffice.

Some advise that 75mm of foundation is required beneath the sand. Of
these some say to use aggregate alone, some say to use a mix of
aggregate and cement.

So my questions are, is an aggregate foundation necessary, and if so
should cement be included? Also, should the sharp sand be mixed with
cement?

Cheers, Adam

The only way of making sure that the slabs stay put is to lay them on a
mortar mix. Providing the ground under the mortar is firm you shouldn't need
hardcore for a light use patio area. But if the soil is soft then you
probably need a sub-base of compacted rubble.

http://www.homebase.co.uk/wcsstore/homebase/en_US/images/p0//HBHowToArticles/articles/howto_buildpatio.html
http://www.focusdiy.co.uk/stry/diy23&bklist=pcat,3,advicecentrecategory,diycatego ry

If you just lay them on sand then you may get tilting and rocking later.