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Posted: Fri Jan 26, 2007 12:21 pm
by zimmi
Hi
Can I use concrete to screed an existing new concrete slab in order to overcome rain damage and uneveness to the original slab. If so what mix ratio and should there be any additives like hardener etc.
Thanks Z 
Posted: Fri Jan 26, 2007 7:38 pm
by lutonlagerlout
as long as the existing is fairly sound and you degrease it and clean it you would be ok overtopping with 100mm of concrete
we normally use 12.5kg of cement to 75 kg of ballast with about a half bucket of clean water to a mix
normally though the garage door will be the issue as your car wont like going up a 100mm step
can this be over come?
if not you might have to use a ronacrete repair mortar just to smooth the surface over look here for some more ideas
regards LLL
Posted: Sat Jan 27, 2007 12:54 pm
by zimmi
Hi LLL
I have looked at the link you provided and I guess that a grano might do the trick. My only concern is the thickness of the screed.
I have an up-and-over garage door that has a support batten (32mmx32mm) running across the floor. My idea was to 'fill' the garage with about 40mm concrete screed and slope it down to the batten to:
(a.) seal off the concrete garage walls and
(b.) cover the existing surface finish.
I cannot lay more than about 40mm of screed. The existing slab projects about 200mm outside the garage door and then there will be a ramp from the edge of the slab down to the driveway level.
I am beginning to feel a little overwhelmed by DIY'ing this. Do you know of anyone in the Harrow Middlesex area that might be prepared to do this small job?
Regards Z
Posted: Sat Jan 27, 2007 7:05 pm
by lutonlagerlout
zimmi like the old builders joke goes;
"no job too small ,because the price wont be" at a guess you would be looking at about £400 upwards for this work
simeon at ronacrete may be able to tell you of one of his fantastic products that can be laid thinly
i'm sure in a recent thread he spoke of an admixture that enabled screed to be laid at 30mm
sorry i dont know any london builders
cheers LLL
Posted: Sat Jan 27, 2007 11:39 pm
by simeonronacrete
Thans for the recommendation lutonlagerlout.
Yes, you can lay a thin bonded screed for a car garage floor, or get a specialist to do it for you.
If you use Ronafix (liquid) with your cement:sand screed you can lay a screed with a minimum thickness of only 10mm on to a sound, prepared concrete slab.
Your screed would be 1:2.5 cement:medium sharp sand gauged with 1:1 Ronafix:water. Bond it to the concrete with a 1:1 Ronafix:cement primer.
Give Donna or Daniel a call on 01279 638 700 if you want more information or a sub-contractor to do it for you.
Also see
www.ronacrete.co.uk
Products
Flooring
Documents
Cementitious
Ronafix for thin screeds and floors
Posted: Mon Jan 29, 2007 9:39 am
by zimmi
Thanks for your help guys. I will contact Ronacrete now and let you know how it goes.
Regards Z