Well, the slab is laid (75% done Saturday and the last 25% on Sunday).

Hired a Belle Premier 100XT diesel mixer.

6 tons of loose ballast, 40 bags of cement (4 bags spare).

After measuring a 5:1 mix using buckets and estimating shovel loads we
settled on 22 shovels of ballast and one 25kg bag of cement per load.
This worked out at six mixer loads per ton (nominally a 110 litre mixer but
this works out at 167 litres; we could have pushed it and mixed a little
more but it was easiest working at one bag of cement per mix). Barrow rated
at 88 litres and two almost full loads so we were somewhere near. However I
can't help thinking that we were nearer 140 - 150 litres and the ballast was
slightly under six tons. Whatever.

The six tons of loose ballast used 36 bags of cement so (all things being
equal) we were working at the suggested six bags per ton.

There wasn't enough ballast.

Went to B&Q Warehouse on Sunday with the trailer and got a 'ton' bag of
ballast and another couple of bags of cement.

With this extra we just scraped home - ended up about a pint short and
scraped all the residue out of the mixer :-)
We didn't get six full mixes out of the bag so reckon there was less than a
ton in there - but nobody knew more than that the bag was rated at 1 ton.
Getting anything out of the builders yard end of B&Q warehouse is a farce.
It took three people over half an hour to organise a fork lift and get the
bag onto the trailer.
Five minute job at Jewson.
However, B&Q is open on Sundays.

So:

assuming my estimate of volume (3.5 cubic metres) was approximately right
the quarry companies who work on 1.5 tons per cubic metre are under
estimating. 2 tons per cubic metre would be closer to the mark.

The contenders were (checking back)

Ballast comapnies - 5.25 tons
Paving Expert - 6.65 tons or 6.3 tons using McCormack's C20 estimator
'practicaldiy' - 7.77 tons

Estimated actual about 6.9 tons.
Could be less if the 'six tons' loose was slightly under and the B&Q bag was
slightly under.
In which case Paving Expert was about spot on.

http://www.pavingexpert.com seems to be pretty good - certainly within 5% -
I am assuming that my slight overshoot was due to the 8"/200mm area round
the edge being slightly larger than estimated in parts.

Thanks to all for the help.

Pictures to be updated on photo bucket shortly.

Slab is now covered in hessian (to give it a string vest) and a layer of
plastic.

Saturday was glorious and sunny.
Sunday was damp and miserable.
Monday is cold, temperature is below 2C, and it is snowing a little.

I am still not at all sure how much I have laid; thinking back one sure way
to know would be to fill the site up with water (inside the damp proof
liner) measuring the water on the way in then pumping it out again. Life is,
however, too short.

Now to start planning the construction of the shed, and waiting for the
weather to warm up enough for block laying.

Cheers

Dave R

Oh, and the valve for the tyre on the builder's barrow packed up over night
Saturday.
Fortunately I had a second barrow (not quite the same shape as a builder's
barrow but it was adequate).

On Feb 8, 12:36 pm, "David WE Roberts" wrote:
Well, the slab is laid (75% done Saturday and the last 25% on Sunday).

Hired a Belle Premier 100XT diesel mixer.

6 tons of loose ballast, 40 bags of cement (4 bags spare).

After measuring a 5:1 mix using buckets and estimating shovel loads we
settled on 22 shovels of ballast and one 25kg bag of cement per load.
This worked out at six mixer loads per ton (nominally a 110 litre mixer but
this works out at 167 litres; we could have pushed it and mixed a little
more but it was easiest working at one bag of cement per mix). Barrow rated
at 88 litres and two almost full loads so we were somewhere near. However I
can't help thinking that we were nearer 140 - 150 litres and the ballast was
slightly under six tons. Whatever.

The six tons of loose ballast used 36 bags of cement so (all things being
equal) we were working at the suggested six bags per ton.

There wasn't enough ballast.

Went to B&Q Warehouse on Sunday with the trailer and got a 'ton' bag of
ballast and another couple of bags of cement.

With this extra we just scraped home - ended up about a pint short and
scraped all the residue out of the mixer :-)
We didn't get six full mixes out of the bag so reckon there was less than a
ton in there - but nobody knew more than that the bag was rated at 1 ton.
Getting anything out of the builders yard end of B&Q warehouse is a farce.
It took three people over half an hour to organise a fork lift and get the
bag onto the trailer.
Five minute job at Jewson.
However, B&Q is open on Sundays.

So:

assuming my estimate of volume (3.5 cubic metres) was approximately right
the quarry companies who work on 1.5 tons per cubic metre are under
estimating. 2 tons per cubic metre would be closer to the mark.

The contenders were (checking back)

Ballast comapnies - 5.25 tons
Paving Expert - 6.65 tons or 6.3 tons using McCormack's C20 estimator
'practicaldiy' - 7.77 tons

Estimated actual about 6.9 tons.
Could be less if the 'six tons' loose was slightly under and the B&Q bag was
slightly under.
In which case Paving Expert was about spot on.

http://www.pavingexpert.comseems to be pretty good - certainly within 5% -
I am assuming that my slight overshoot was due to the 8"/200mm area round
the edge being slightly larger than estimated in parts.

Thanks to all for the help.

Pictures to be updated on photo bucket shortly.

Slab is now covered in hessian (to give it a string vest) and a layer of
plastic.

Saturday was glorious and sunny.
Sunday was damp and miserable.
Monday is cold, temperature is below 2C, and it is snowing a little.

I am still not at all sure how much I have laid; thinking back one sure way
to know would be to fill the site up with water (inside the damp proof
liner) measuring the water on the way in then pumping it out again. Life is,
however, too short.

Now to start planning the construction of the shed, and waiting for the
weather to warm up enough for block laying.

Cheers

Dave R

Oh, and the valve for the tyre on the builder's barrow packed up over night
Saturday.
Fortunately I had a second barrow (not quite the same shape as a builder's
barrow but it was adequate).

nice one!
NB if you had had enough ballast would you have finished in 1 day? how
many pairs of hands all told? how do you feel?!

Seriously I hope you are well pleased, not least because you *know*
it's done right with proper materials, no unnecessary rushing, no
unavoidable bodges, or typical hassles with readymix or truckmix etc..

Cheers
JimK

"JimK" wrote in message
...
snip

nice one!
NB if you had had enough ballast would you have finished in 1 day? how
many pairs of hands all told? how do you feel?!

Seriously I hope you are well pleased, not least because you *know*
it's done right with proper materials, no unnecessary rushing, no
unavoidable bodges, or typical hassles with readymix or truckmix etc..

We didn't run out of ballast until half way through Sunday.

There were two of us full time (myself & lady wife) and two more for about
three hours (friend and his partner).
Two people sharing the mixing and barrowing did speed things up.
We had decided not to push for doing the whole slab in one day, which was
wise.
We were all pretty tired at the end of the first day.

It was obvious that trying to barrow a load of ready mixed stuff in under an
hour would have more or less killed me, even with another barrow runner and
without the added complication of trying to get it all spread and levelled
before the mixer went off site.

3.5 cubic metres is doable in one (summer) day if you plan to work from
about 09:00 through to 19:00.
We had to stop and clear up when it started getting dark about 16:30.

Tired, but not as tired as after Saturday.
Sunday was only a quarter of the slab, with a lot of pratting about at B&Q.

After the rain overnight I know that I have a couple of low spots - only a
few millimetres but enough to form a very shallow puddle.
So no playing billiards on the concrete base :-(

The good news is we managed to get the slab laid in what looks like the only
suitable two day slot this month.
By Thursday we expect heavy snow.

Cheers

Dave R

David WE Roberts wrote:

We didn't run out of ballast until half way through Sunday.

There were two of us full time (myself & lady wife) and two more for
about three hours (friend and his partner).
Two people sharing the mixing and barrowing did speed things up.
We had decided not to push for doing the whole slab in one day, which
was wise.
We were all pretty tired at the end of the first day.

It was obvious that trying to barrow a load of ready mixed stuff in
under an hour would have more or less killed me, even with another
barrow runner and without the added complication of trying to get it
all spread and levelled before the mixer went off site.

3.5 cubic metres is doable in one (summer) day if you plan to work
from about 09:00 through to 19:00.
We had to stop and clear up when it started getting dark about 16:30.

Tired, but not as tired as after Saturday.
Sunday was only a quarter of the slab, with a lot of pratting about
at B&Q.
After the rain overnight I know that I have a couple of low spots -
only a few millimetres but enough to form a very shallow puddle.
So no playing billiards on the concrete base :-(

The good news is we managed to get the slab laid in what looks like
the only suitable two day slot this month.
By Thursday we expect heavy snow.

Cheers

Dave R

Did you put in any mesh or did you not bother with it?

I wouldn't worry about a few low spots here and there - these are
unavoidable even for a professional, which is why god invented tiles and/or
carpets.

If it's smooth, you can paint it more easily when the time comes, and even
now it should be 'trowelable' if you still want to give it another blast
over should you need to, but this is personal choice and for a shed floor I
wouldn't worry too much - a bit of 'roughness' isn't a bad thing WRT grip,
especially for older people (!).

Don't worry about the weather - as long as it stays damp, the concrete will
set harder and with fewer cracks, and frost will do nothing unless it's a
deep heavy frost and even then it would only cause a light spalling on the
face, easily repaired in warmer weather with a strong mix of sand/cement.

If you want your floor to remain 'pristine', you'll have to put something
down prior to building the walls.
I suggest a sheet of membrane about 3ft wide, and place it under the DPC and
build on it, then when you've finished, slice it off with a sharp blade -
the remainder that stays in acts as a double DPC
What have you chosen for the walls? - there's a lightweight block which is
fairly cheap and easy to use - we built a garage from them about 8 years
ago, they are made with what looks like small balls stuck together, but the
balls are air filled, it's like building with aero bars!! - but they have no
weatherproofing qualities so they'll need to be rendered externally, which
is easily offset by the price, I think they were about 30% cheaper than
cocnrete blocks and about a third of the weight.


--
Phil L
RSRL Tipster Of The Year 2008

Phil L wrote:

about 8 years ago, they are made with what looks like small balls
stuck together, but the balls are air filled, it's like building with
aero bars!! - but they have no weatherproofing qualities so they'll
need to be rendered externally, which is easily offset by the price,
I think they were about 30% cheaper than cocnrete blocks and about a
third of the weight.

Search google UK for pumice blocks

--
Phil L
RSRL Tipster Of The Year 2008

"Phil L" wrote in message
om...
David WE Roberts wrote:

snip

Did you put in any mesh or did you not bother with it?

We put down one layer of mesh, and incorporated some old (but clean)
concrete fence posts with built in reinforcing into the deep bits.

I wouldn't worry about a few low spots here and there - these are
unavoidable even for a professional, which is why god invented tiles
and/or carpets.

If it's smooth, you can paint it more easily when the time comes, and even
now it should be 'trowelable' if you still want to give it another blast
over should you need to, but this is personal choice and for a shed floor
I wouldn't worry too much - a bit of 'roughness' isn't a bad thing WRT
grip, especially for older people (!).

Don't worry about the weather - as long as it stays damp, the concrete
will set harder and with fewer cracks, and frost will do nothing unless
it's a deep heavy frost and even then it would only cause a light spalling
on the face, easily repaired in warmer weather with a strong mix of
sand/cement.

If you want your floor to remain 'pristine', you'll have to put something
down prior to building the walls.
I suggest a sheet of membrane about 3ft wide, and place it under the DPC
and build on it, then when you've finished, slice it off with a sharp
blade - the remainder that stays in acts as a double DPC
What have you chosen for the walls? - there's a lightweight block which is
fairly cheap and easy to use - we built a garage from them about 8 years
ago, they are made with what looks like small balls stuck together, but
the balls are air filled, it's like building with aero bars!! - but they
have no weatherproofing qualities so they'll need to be rendered
externally, which is easily offset by the price, I think they were about
30% cheaper than cocnrete blocks and about a third of the weight.

Had a look at some - they are like rice crispies.
Lightness is a plus, having to render is not.
We were planning not to render, just to paint (cost is less important than
my back on this one) which led us to concrete blocks.
Heavy, not especially good thermal insulation, but solid.

If you know of a structurally strong lightweight block that is also
weatherproof then please let me know :-)

I assume the concrete blocks are a bit hard to drill into, as well, for
fixing insulation, shelves etc.

Chosing the blocks is the next stage.

Cheers

Dave R

In message , David WE Roberts
writes
Well, the slab is laid (75% done Saturday and the last 25% on Sunday).

Well done:-)

Big bags of building sand from my merchant are 850kg. Don't know about
bagged gravel.

Now you are in practice, I have 12 cu/m to lay in the next week or so...

regards
--
Tim Lamb

On Mon, 8 Feb 2010 12:36:08 -0000, David WE Roberts wrote:

Well, the slab is laid (75% done Saturday and the last 25% on Sunday).
Went to B&Q Warehouse on Sunday with the trailer and got a 'ton' bag of
ballast and another couple of bags of cement.

With this extra we just scraped home - ended up about a pint short and
scraped all the residue out of the mixer :-)
We didn't get six full mixes out of the bag so reckon there was less than a
ton in there - but nobody knew more than that the bag was rated at 1 ton.

I don't know about B&Q, but Wickes do similar bags and quote them as
minumum 850kg.

SteveW

"John Rumm" wrote in message
...
David WE Roberts wrote:

There were two of us full time (myself & lady wife) and two more for
about three hours (friend and his partner).
Two people sharing the mixing and barrowing did speed things up.
We had decided not to push for doing the whole slab in one day, which was
wise.
We were all pretty tired at the end of the first day.


How did you handle the transition from the first days pour to the second?

As shown in the photos we put some wood across to form a vertical barrier,
and had the reinforcing under it.
The concrete was still 'green' the following morning and so seemed fine to
join to.
Only time will tell.

I would have been more cautious in the summer where the concrete could have
gone off quite a lot more but an overnight pause at this time of year seemed
O.K.

There is an inherent problem in stopping a pour of reinforced concrete - you
want the sheets of reinforcing to overlap and you can't do that and get a
clean vertical joint.

Professionals have special shuttering with holes in (mmm......) and put
reinforcing bars through the holes to bind the slabs together.

Couldn't face the added complication and so decided to leave a sloping joint
with the top 50mm vertical from the wood acrosss the slab.
The top bit of wood enabled us to level up to it.

Cheers

Dave R

"Steve Walker" wrote in message
...
On Mon, 8 Feb 2010 12:36:08 -0000, David WE Roberts wrote:

Well, the slab is laid (75% done Saturday and the last 25% on Sunday).
Went to B&Q Warehouse on Sunday with the trailer and got a 'ton' bag of
ballast and another couple of bags of cement.

With this extra we just scraped home - ended up about a pint short and
scraped all the residue out of the mixer :-)
We didn't get six full mixes out of the bag so reckon there was less than
a
ton in there - but nobody knew more than that the bag was rated at 1 ton.

I don't know about B&Q, but Wickes do similar bags and quote them as
minumum 850kg.

Jewson also quote a minimum of about 850kg - which means you could get
anything from there upwards but most likely near the minimum.
It would be interesting some time to get a few bags and dry them then put
them on a weighbridge.
No doubt the results would be much like drying a pound of bacon - some
suppliers would have quite a bit of water in there.

The B&Q bag was a lot drier than the loose ballast - we could tell when we
had to add more water to each mix.

"Tim Lamb" wrote in message
...
In message , David WE Roberts
writes
Well, the slab is laid (75% done Saturday and the last 25% on Sunday).

Well done:-)

Big bags of building sand from my merchant are 850kg. Don't know about
bagged gravel.

Now you are in practice, I have 12 cu/m to lay in the next week or so...

£100 per cubic metre sound about right (plus materials) ?

In message , David WE Roberts
writes

"Tim Lamb" wrote in message
.. .
In message , David WE Roberts
writes
Well, the slab is laid (75% done Saturday and the last 25% on Sunday).

Well done:-)

Big bags of building sand from my merchant are 850kg. Don't know
about bagged gravel.

Now you are in practice, I have 12 cu/m to lay in the next week or so...

£100 per cubic metre sound about right (plus materials) ?

Fortunately I can either back the readimix wagon up to the site or move
mixed concrete in the farm grain bucket. Tamping may be an issue as the
building is 6.5m wide and 13.5 long. Two drops clearly but splitting it
into three may make the job easier.

Major concession on my last delivery as they waived the *empty haul*
charge.

regards

--
Tim Lamb

David WE Roberts wrote:
"Steve Walker" wrote in message
...
On Mon, 8 Feb 2010 12:36:08 -0000, David WE Roberts wrote:

Well, the slab is laid (75% done Saturday and the last 25% on
Sunday). Went to B&Q Warehouse on Sunday with the trailer and got a
'ton' bag of ballast and another couple of bags of cement.

With this extra we just scraped home - ended up about a pint short
and scraped all the residue out of the mixer :-)
We didn't get six full mixes out of the bag so reckon there was
less than a
ton in there - but nobody knew more than that the bag was rated at
1 ton.

I don't know about B&Q, but Wickes do similar bags and quote them as
minumum 850kg.

Jewson also quote a minimum of about 850kg - which means you could get
anything from there upwards but most likely near the minimum.
It would be interesting some time to get a few bags and dry them then
put them on a weighbridge.
No doubt the results would be much like drying a pound of bacon - some
suppliers would have quite a bit of water in there.

The B&Q bag was a lot drier than the loose ballast - we could tell
when we had to add more water to each mix.

Couple of years ago I did a job in a local factory owned by the Tarmac
Group. They packaged sand, ballast, type one, gravel, slate chippings etc
into 25kg sacks & 850k big bags.

They had stocks of bags printed up for Wickes, B&Q, Homebase, Travis
Perkins, Jewson, Buildbase, Selco etc. Everything came from the same great
big heap :-)


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

"David WE Roberts" wrote in message
...
Well, the slab is laid (75% done Saturday and the last 25% on Sunday).

Hired a Belle Premier 100XT diesel mixer.



In case others are interested there are full calculators on line to do the
quantities for you (pavingexpert.com)

"Rick Hughes" wrote in message
...

"David WE Roberts" wrote in message
...
Well, the slab is laid (75% done Saturday and the last 25% on Sunday).

Hired a Belle Premier 100XT diesel mixer.



In case others are interested there are full calculators on line to do the
quantities for you (pavingexpert.com)

If you read back a little we are discussing how accurate these estimators
are.