Foundation height errors - Advice required

[TrevorL]

I hope some of you may be able to help me.
I am building a double garage about 6m x 5.5m and have got as far as digging and filling the trench filled 450mm wide strip foundation. I have set the height at 300mm below dpc.
I have a difference in height around the foundations of about 2 cm, and would like to know if this an acceptable error to rectify by altering the mortar thickness?
I was going to use 140mm high blocks up to ground level but have since found out the blocks I was going to use are no longer made and the alternatives may take a week or so for delivery. If I use facing bricks up to dpc, would they be able to cope with the height difference on the foundations as well as blocks, where the load would be spread over a larger area?
And would it be alright if I put blocks on top of facing bricks, because I know they expand and contract in different ways.

Also I would like to know the best hardcore to use for the concrete floor - I was going to use MOT type 1.

Sorry for all the questions.
Many thanks.

[lutonlagerlout]

you rough sod matt
20mm out in 300mm is do-able but if it is 20 low you will need some stiff mortar
if it is 20 high some wet mortar
why oh why cant ppl get concrete level in foundations??
its so easy ,then the whole job just whizzes up i suggest putting some datums in on each corner so the brickie has something to work to
cheers LLL

[lutonlagerlout]

you rough sod matt

sorry should read "you rough sod trevor"
brains gone wobbly again
cheers LLL

[Dave_L]

This is pretty much what we'll be doing Monday next - hooking out the footings for an extension to a nursing home and pouring the founds. Not really something I have done much with really, so looking foward to it. Might even take me camera with me

[lutonlagerlout]

believe me dave,it makes live so much easier for everyone if the crete is level + or - 5mm.
groundworkers do it all the time to me "just cut a few blocks round that hump mate" "we had .5 of crete left over so we had to use it" "does it really matter if its not level?"
and the coup de grace "i leveled it with a rake" one corner was 40mm high on this job
regards LLL

[TrevorL]

Many thanks for the advice.
It was a bit of a rush to put the concrete in and I should have had more help.
Have any of you ever used a device called a "Bricky"? It's used to lay the mortar at the correct thickness - if I don't get on with it I will have to hire a real bricky.

All the best
Trevor

[Stuarty]

Is that the bar type thing with a gap that sits on the wall and you basically screed the mortar along it ?

Brickwork is all about taking your time if your a novice. Brickies take a long time to perfect their art.

[lutonlagerlout]

if you want to lay 100 bricks a day the "brickie" is ok,realistically hire a bricklayer for a day and a labourer and watch 800-1000 bricks go in nice and straight
cheers LLL :laugh:

[TrevorL]

Yes, it is the bar type with a gap in the middle.
The only problem I could imagine is the tolerance on the length of the brick. A good bricklayer would alter the mortar thickness to cope with this but with the "Bricky" you are stuck with a 10mm joint!
If I don't get on with it I will hire a bricklayer.

[lutonlagerlout]

better to use profiles trevor, i have laid 100's of thousands of bricks and believe me they are not all 100% straight.
any minor defect will be magnified by the brickie, btw a bricklayer in your part of the world should cost 130-160 a day as a rough guide
cheers LLL

[TrevorL]

Many thanks for that. I will take your advice and use profiles as well.
The weather hasn't been that good recently so I haven't made any progress. Idealy I need a couple of dry days before I start laying the foundation blocks and correct the height errors.
If I'm not happy with my progress or quality of my work I will definitely employ a real bricky.

All the best
Trevor

[Dave_L]

believe me dave,it makes live so much easier for everyone if the crete is level + or - 5mm.
groundworkers do it all the time to me "just cut a few blocks round that hump mate" "we had .5 of crete left over so we had to use it" "does it really matter if its not level?"
and the coup de grace "i leveled it with a rake" one corner was 40mm high on this job
regards LLL

Been digging and pouring concrete into the foundations today for a large extension to a care home today (day 2) - I was mindful of your post LLL!

Better to be a little bit low than too high with the concrete though.

[Ted]

Type 1 is the best for your sub-base IMO.

I'm a concrete person not a brickie. My view would be that if you messed up the foundations by 2cm, I would get a pro in for the brickwork. Not only have you got to overcome the 2cm now, but you want the brickwork to look excellent; no-one is going to see your foundation mistake.

[lutonlagerlout]

Better to be a little bit low than too high with the concrete though.

this is a common mistake dave,maybe for floors driveways and roads but with BWK you are normally in the gound anyway so the first 4 courses wont be seen
i'm sure your crete will be spot on dave
cheers
LLL

[seanandruby]

ive seen some rough concrete foundations. usually because some groundworkers use for levels, nails, spray paint even guess work. i find lamp irons ( thats road pins to you ) knocked in the footings do the levels using coloured tape. make the level bottom of tape so that when you pore the crete the tape is still showing above . when complete smooth off so theres no high points, then hook pins out with shovel smooth pinholes job done. hope this helps first timers.