I posted here earlier in the week and some kind souls pointed me in the
right direction, clarifying what I should lay my patio on. But I need a
bit more clarification please.

After whacking down my sub-base I am putting down a drymix mortar to lay
the slabs onto. It seems one part cement to four parts sand is the right
ratio - correct? I had read that the sand for patio work should be sharp
sand (as it 'locks' in place) but I see that pavingexpert.com recommends
that soft sand be used for mixing up mortar. Which is correct? If it
should be soft sand what would the result of using sharp sand be? I have
already ordered the (sharp) sand. I went through what we wanted to do
with someone at the builders merchant and he seemed to agree that we
were on the right track, so hopefully this is not our first stumbling
block.

I was also recommended to put down extra cement at the sides of the
patio to keep the sand in - should this be pure cement (put down dry, as
the mortar?) or just a mortar mix with a higher ratio of cement in (if
so what ratio).

Apologies for the dumb questions but this is all new to me. I have this
week off work this week to do this - I want to be sitting on the patio
having a beer by Friday. In any spare moments during the process I also
have to decorate the kitchen........

Many thanks,
Iain

The message
from Iain Robinson contains these words:

I posted here earlier in the week and some kind souls pointed me in the
right direction, clarifying what I should lay my patio on. But I need a
bit more clarification please.

After whacking down my sub-base I am putting down a drymix mortar to lay
the slabs onto. It seems one part cement to four parts sand is the right
ratio - correct? I had read that the sand for patio work should be sharp
sand (as it 'locks' in place) but I see that pavingexpert.com recommends
that soft sand be used for mixing up mortar. Which is correct?

Save yourself a lot of grief, do it the proper way first time.

www.pavingexpert is run by an ex-urgler expert with a national
reputation for the quality of his professional work. He does
award-winning work for the National Trust etc. Having followed his
excellent website advice myself I can absolutely recommend it; you can
also ask for personal help via his website iirc.

Janet.

"Iain Robinson" wrote in message
...
I posted here earlier in the week and some kind souls pointed me in the
right direction, clarifying what I should lay my patio on. But I need a
bit more clarification please.

After whacking down my sub-base I am putting down a drymix mortar to lay
the slabs onto. It seems one part cement to four parts sand is the right
ratio - correct? I had read that the sand for patio work should be sharp
sand (as it 'locks' in place) but I see that pavingexpert.com recommends
that soft sand be used for mixing up mortar. Which is correct? If it
should be soft sand what would the result of using sharp sand be? I have
already ordered the (sharp) sand. I went through what we wanted to do
with someone at the builders merchant and he seemed to agree that we
were on the right track, so hopefully this is not our first stumbling
block.

1:4 is OK, you could go for a weaker mix if you like. Sharp sand is OK too.
I
don't know what advantage could be gleaned from using soft sand in this
application. Soft sand is usually used for bricklaying or pointing as it
makes
the mortar 'handle' well. Am I correct in assuming that by 'drymix' you mean
that you lay down a dry mortar mix, place the slabs on top, then let
atmospheric
moisture set it over time? If so, then its wet properties won't even be an
issue.
Sharp sand gives a stronger material, which is not so easy to manipulate
( in a wet mix state ) as mortar made with soft sand. If you have to use
sharp
sand ( because you have lots of it lying around! ) for wet work i.e.
bricklaying
or laying slabs on a wet solid bed of mortar, a little plasticiser in it
will improve
its workability tremendously.

I was also recommended to put down extra cement at the sides of the
patio to keep the sand in - should this be pure cement (put down dry, as
the mortar?) or just a mortar mix with a higher ratio of cement in (if
so what ratio).

Never use pure cement on its on. It will crack. Use 1:4 again. The highest
ratio you can use is 1:3, but this is a strong mix, and is only suitable for
stone walls etc. 1:4 is plenty strong enough to keep sand fro escaping your
patio. To give you some idea of mix ratios, 1:3 is the strongest useful mix,
1:4 is OK for mortar, 1:5 is an appropriate mix concrete made with
3/4"-to-dust
ballast and you can go down to 1:6 in low strength applications ( behind a
firegrate as infill etc. Any weaker and it will get sandy over time in
exposed areas.

Apologies for the dumb questions but this is all new to me. I have this
week off work this week to do this - I want to be sitting on the patio
having a beer by Friday. In any spare moments during the process I also
have to decorate the kitchen........

Many thanks,
Iain

Remember that cement is as caustic as oven cleaner, wear gloves, especially
if you
are using it wetmix, otherwise you won't have any skin on the tips of your
fingers at
the end of the day.

Andy.

"andrewpreece" wrote in message
...

"Iain Robinson" wrote in message
...
I posted here earlier in the week and some kind souls pointed me in the
right direction, clarifying what I should lay my patio on. But I need a
bit more clarification please.

After whacking down my sub-base I am putting down a drymix mortar to lay
the slabs onto. It seems one part cement to four parts sand is the right
ratio - correct? I had read that the sand for patio work should be sharp
sand (as it 'locks' in place) but I see that pavingexpert.com recommends
that soft sand be used for mixing up mortar. Which is correct? If it
should be soft sand what would the result of using sharp sand be? I have
already ordered the (sharp) sand. I went through what we wanted to do
with someone at the builders merchant and he seemed to agree that we
were on the right track, so hopefully this is not our first stumbling
block.

1:4 is OK, you could go for a weaker mix if you like. Sharp sand is OK
too.
I
don't know what advantage could be gleaned from using soft sand in this
application. Soft sand is usually used for bricklaying or pointing as it
makes
the mortar 'handle' well. Am I correct in assuming that by 'drymix' you
mean
that you lay down a dry mortar mix, place the slabs on top, then let
atmospheric
moisture set it over time? If so, then its wet properties won't even be an
issue.
Sharp sand gives a stronger material, which is not so easy to manipulate
( in a wet mix state ) as mortar made with soft sand. If you have to use
sharp
sand ( because you have lots of it lying around! ) for wet work i.e.
bricklaying
or laying slabs on a wet solid bed of mortar, a little plasticiser in it
will improve
its workability tremendously.

I was also recommended to put down extra cement at the sides of the
patio to keep the sand in - should this be pure cement (put down dry, as
the mortar?) or just a mortar mix with a higher ratio of cement in (if
so what ratio).

Never use pure cement on its on. It will crack. Use 1:4 again. The highest
ratio you can use is 1:3, but this is a strong mix, and is only suitable
for
stone walls etc. 1:4 is plenty strong enough to keep sand fro escaping
your
patio. To give you some idea of mix ratios, 1:3 is the strongest useful
mix,
1:4 is OK for mortar, 1:5 is an appropriate mix concrete made with
3/4"-to-dust
ballast and you can go down to 1:6 in low strength applications ( behind a
firegrate as infill etc. Any weaker and it will get sandy over time in
exposed areas.

Apologies for the dumb questions but this is all new to me. I have this
week off work this week to do this - I want to be sitting on the patio
having a beer by Friday. In any spare moments during the process I also
have to decorate the kitchen........

Many thanks,
Iain

Remember that cement is as caustic as oven cleaner, wear gloves,
especially
if you
are using it wetmix, otherwise you won't have any skin on the tips of your
fingers at
the end of the day.

Andy.



Oh, and make sure your patio slopes a little ( away from the house ) in
order to
avoid pools of atanding water. 1:60 is often mentioned as a reasonable
slope.

Andy

The message
from Iain Robinson contains these words:

I posted here earlier in the week and some kind souls pointed me in the
right direction, clarifying what I should lay my patio on. But I need a
bit more clarification please.

After whacking down my sub-base I am putting down a drymix mortar to lay
the slabs onto. It seems one part cement to four parts sand is the right
ratio - correct?

It depends how strong the mortar needs to be. 4:1 will set *VERY* hard.
If I were doing the job I'd use hoggin, or if it was really necessary,
mix the sand cement at (say) 10:1 or weaker.

Lay the sand or drymix flat, then scoop out a shallow hollow in the
middle of where the block should be, amounting to about half the area of
each slab. Yhis allows you to tamp down the slabs till they are all
level, and IMO, a bit of cement in the sand helps maintain the level,
unless you are a - ahem - paving expert.

I had read that the sand for patio work should be sharp
sand (as it 'locks' in place) but I see that pavingexpert.com recommends
that soft sand be used for mixing up mortar. Which is correct?

Knowing Cormaic (from posts here) the proprietor of pavingexpert.com,
I'd say he was.

If it
should be soft sand what would the result of using sharp sand be? I have
already ordered the (sharp) sand. I went through what we wanted to do
with someone at the builders merchant and he seemed to agree that we
were on the right track, so hopefully this is not our first stumbling
block.

I'd ask Cormaic if I were you.

I was also recommended to put down extra cement at the sides of the
patio to keep the sand in - should this be pure cement (put down dry, as
the mortar?) or just a mortar mix with a higher ratio of cement in (if
so what ratio).

Yes, a nice touch, and also tends to prevent mice etc undermining it. If
I were doing it I'd extend the rubble base enough to make a retaining
wall one brick high, either flat or on edge. You may then use your 4:1
mortar mix to lay the course so it doesn't fall apart in no time.

Apologies for the dumb questions but this is all new to me. I have this
week off work this week to do this - I want to be sitting on the patio
having a beer by Friday. In any spare moments during the process I also
have to decorate the kitchen........

They're not dumb questions at all - if you've never done it, how would
you know?

--
Rusty
Emus to: horrid dot squeak snailything zetnet point co full-stop uk
http://www.users.zetnet.co.uk/hi-fi/

Iain Robinson wrote:
:: I posted here earlier in the week and some kind souls pointed me in the
:: right direction, clarifying what I should lay my patio on. But I need a
:: bit more clarification please.
::
:: After whacking down my sub-base I am putting down a drymix mortar to lay
:: the slabs onto. It seems one part cement to four parts sand is the right
:: ratio - correct? I had read that the sand for patio work should be sharp
:: sand (as it 'locks' in place) but I see that pavingexpert.com recommends
:: that soft sand be used for mixing up mortar. Which is correct? If it
:: should be soft sand what would the result of using sharp sand be? I have
:: already ordered the (sharp) sand. I went through what we wanted to do
:: with someone at the builders merchant and he seemed to agree that we
:: were on the right track, so hopefully this is not our first stumbling
:: block.
::

There's little difference in using soft or sharp sand in this instance, and
4:1 is a very strong mix for laying slabs on, I'd suggest 10:1 - you aren't
sticking them to anything, merely providing a semi-hard base, note the use
of the word 'semi' - you want water to be able to drain through - any pooled
water underneath or around the flags will cause all manner of problems when
it freezes, this is one of the reasons for good drainage....they used to
just lay them on sand and many firms still do, especially for patios and
paths, cement sometimes gets used under driveways, but even these are often
done on a bed of sand.
Another point; you say 'drymix'? - you aren't mixing it in the conventional
way? - IE with a mixer or by hand? - none of this is needed, all you need to
do is rake your sand level, throw on a sprinkling of cement and rake it into
the bed, about 2KG of cement per metre, meaning you will get 12M out of one
bag of cement and this is strong enough to run cars on.


:: I was also recommended to put down extra cement at the sides of the
:: patio to keep the sand in - should this be pure cement (put down dry, as
:: the mortar?) or just a mortar mix with a higher ratio of cement in (if
:: so what ratio).
::

Don't use pure cement as it's hideous when dried, a mixture of around 4:1,
but mixed in the conventional way, (with a drop of fairy liquid [1] for
plasticising) is more than adequate, you can do this the day after your
flags are all down, just go around the edges with a bucket of mortar and a
trowel, not forgetting to leave the surface below that of the flags, so that
you can fill in with bark or chippings if you want, the only problems I can
forsee doing it this way is that it may hold the water if you do it
completely, to counteract this, go along it with a garden fork and puncture
a few holes through after you have finished and prior to dressing with
stones/bark.

:: Apologies for the dumb questions but this is all new to me. I have this
:: week off work this week to do this - I want to be sitting on the patio
:: having a beer by Friday. In any spare moments during the process I also
:: have to decorate the kitchen........

Mmmm...beer....!
BTW - A week? - how big is it?.....doing it on your own, you should be able
to screed (get your sand/cement base ready) and lay about 30 sq m per
day.....

[1]
Don't bother buying mortar plasticiser unless you intend doing a lot of
building, you don't need anything in the screed, but in the mortar for the
edges, use about a teaspoonful of W-U-L per bucketfull of mortar (about 4
shovels of sand and one of cement - *don't* overdo it on the cement, a
common mistake by those not accustomed to working with it!)


HTH

--
If God had intended us to drink beer, He would have given us stomachs.

Phil L wrote:
Iain Robinson wrote:
:: I posted here earlier in the week and some kind souls pointed me in the
:: right direction, clarifying what I should lay my patio on. But I need a
:: bit more clarification please.
::
:: After whacking down my sub-base I am putting down a drymix mortar to lay
:: the slabs onto. It seems one part cement to four parts sand is the right
:: ratio - correct? I had read that the sand for patio work should be sharp
:: sand (as it 'locks' in place) but I see that pavingexpert.com recommends
:: that soft sand be used for mixing up mortar. Which is correct? If it
:: should be soft sand what would the result of using sharp sand be? I have
:: already ordered the (sharp) sand. I went through what we wanted to do
:: with someone at the builders merchant and he seemed to agree that we
:: were on the right track, so hopefully this is not our first stumbling
:: block.
::

There's little difference in using soft or sharp sand in this instance, and
4:1 is a very strong mix for laying slabs on, I'd suggest 10:1 - you aren't
sticking them to anything, merely providing a semi-hard base, note the use
of the word 'semi' - you want water to be able to drain through - any pooled
water underneath or around the flags will cause all manner of problems when
it freezes, this is one of the reasons for good drainage....they used to
just lay them on sand and many firms still do, especially for patios and
paths, cement sometimes gets used under driveways, but even these are often
done on a bed of sand.
Another point; you say 'drymix'? - you aren't mixing it in the conventional
way? - IE with a mixer or by hand? - none of this is needed, all you need to
do is rake your sand level, throw on a sprinkling of cement and rake it into
the bed, about 2KG of cement per metre, meaning you will get 12M out of one
bag of cement and this is strong enough to run cars on.


:: I was also recommended to put down extra cement at the sides of the
:: patio to keep the sand in - should this be pure cement (put down dry, as
:: the mortar?) or just a mortar mix with a higher ratio of cement in (if
:: so what ratio).
::

Don't use pure cement as it's hideous when dried, a mixture of around 4:1,
but mixed in the conventional way, (with a drop of fairy liquid [1] for
plasticising) is more than adequate, you can do this the day after your
flags are all down, just go around the edges with a bucket of mortar and a
trowel, not forgetting to leave the surface below that of the flags, so that
you can fill in with bark or chippings if you want, the only problems I can
forsee doing it this way is that it may hold the water if you do it
completely, to counteract this, go along it with a garden fork and puncture
a few holes through after you have finished and prior to dressing with
stones/bark.

:: Apologies for the dumb questions but this is all new to me. I have this
:: week off work this week to do this - I want to be sitting on the patio
:: having a beer by Friday. In any spare moments during the process I also
:: have to decorate the kitchen........

Mmmm...beer....!
BTW - A week? - how big is it?.....doing it on your own, you should be able
to screed (get your sand/cement base ready) and lay about 30 sq m per
day.....

[1]
Don't bother buying mortar plasticiser unless you intend doing a lot of
building, you don't need anything in the screed, but in the mortar for the
edges, use about a teaspoonful of W-U-L per bucketfull of mortar (about 4
shovels of sand and one of cement - *don't* overdo it on the cement, a
common mistake by those not accustomed to working with it!)


HTH


Thanks Phil. It's not big (much less than 30 sq m) but being completely
new to all this and having a 3 year old under our feet will no doubt
slow us down, hence the more conservative time frame.

Iain Robinson wrote:
I posted here earlier in the week and some kind souls pointed me in the
right direction, clarifying what I should lay my patio on. But I need a
bit more clarification please.

After whacking down my sub-base I am putting down a drymix mortar to lay
the slabs onto. It seems one part cement to four parts sand is the right
ratio - correct? I had read that the sand for patio work should be sharp
sand (as it 'locks' in place) but I see that pavingexpert.com recommends
that soft sand be used for mixing up mortar. Which is correct? If it
should be soft sand what would the result of using sharp sand be? I have
already ordered the (sharp) sand. I went through what we wanted to do
with someone at the builders merchant and he seemed to agree that we
were on the right track, so hopefully this is not our first stumbling
block.

I was also recommended to put down extra cement at the sides of the
patio to keep the sand in - should this be pure cement (put down dry, as
the mortar?) or just a mortar mix with a higher ratio of cement in (if
so what ratio).

Apologies for the dumb questions but this is all new to me. I have this
week off work this week to do this - I want to be sitting on the patio
having a beer by Friday. In any spare moments during the process I also
have to decorate the kitchen........

Many thanks,
Iain

Thanks to everyone for their replies - I'm adjusting my drymix
accordingly. One more question however - as I'm using a drymix to lay
the slabs onto do I deliberately wet the patio to set the process off or
just let nature take it's course? Also, I'm wondering if I have to not
walk on the patio for longer than normal. 24hrs was mentioned but that
may not have been for a drymix base. I've seen wetting the finished
slabs recommended to help 'settle' it all in but wonder if there are any
issues with this on a drymix base?

As ever, any advice appreciated.
Iain

In article ,
Iain Robinson writes:
|
| Thanks to everyone for their replies - I'm adjusting my drymix
| accordingly. One more question however - as I'm using a drymix to lay
| the slabs onto do I deliberately wet the patio to set the process off or
| just let nature take it's course? Also, I'm wondering if I have to not
| walk on the patio for longer than normal. 24hrs was mentioned but that
| may not have been for a drymix base. I've seen wetting the finished
| slabs recommended to help 'settle' it all in but wonder if there are any
| issues with this on a drymix base?

Well, one of the reasons that I laid on sand and use a weak drymix
for grouting, is that it makes it easy to fix problems. If you
are in ANY doubt about getting it right first time, don't cement
anything down that you don't have to. No, slabs laid on sand (and
even on many soils) don't shift - if you do it right.


Regards,
Nick Maclaren.