Leveling compound advice

[kevsterdiy]

Hi.

I've looked at the Wiki but can't quite get what I think I need to know.

Recently had a garage extention to be used a a hobby workshop. No cars will be driven on this section.

I wish to level the concrete base because it wasn't leveled good enough.

Base is a concrete slab of ready mix, raft style slab.

It didn't have a dpm built in it but the walls have a damp course.

I'm looking to level from 1-2mm deep up to 8-10mm in the odd place.

Then I wish to lay some kind of flooring such as lino or rubber type tiles or carpet tiles.

What type of leveling compound is suitable that is easy to level?

Then do i need to seal/liquid dpm to help with any damp rising up?

Maybe just garage floor paint prior to floor covering?

Thanks

 

[Doggit]

Put down a liquid dpm first, throw dry sharp sand on before it dries, but make sure you brush off the excess sand after it's dried. Self levelling compounds don't actually self level, so you need to find you're highest point in the garage to work outwards from. Drill and rawlplug the holes, then using a spirit level, set in screws to give you the level you've got to work towards. You'll need one person to mix the SLC, and another to lay it down and move it around to get to the level of the screw heads. You'll also want a spiked roller to get the air out of the floor, and possibly spiked shoes if you're going to walk in the SLC. Mix the SLC on a medium speed (a high speed will mix air in to the mix) and don't add too much extra water as although it'll make the mix move easier, it'll weaken it, and give all sorts of other problems.

 

[kevsterdiy]

Thanks for that. As for the type of SLC?

 

[kevsterdiy]

Logic makes me think would I not prime (pva?) the uneven surface first then use SLC and then liquid dpm. Then paint and do flooring.
Or unless the SLC won't like the potential damp slab?

 

[kevsterdiy]

now i am really confused a liquid dpm i have been looking at has some FAQ in the website, which implies this is useless for me!?

Q I have coated my concrete floor with this material to form a DPM. Can I now lay floor tiles/a levelling screed/carpet?
A No. In order to hold down the pressure of water from under the floor, you must apply a minimum thickness of 50mm of a sand/cement screed. Thicker screeds may be required depending on the use of the floor.

http://www.bostik.co.uk/diy/product/bostik/Damp-Proofer-Waterproofer/287/faq

So do i need to look to level the floor with a concrete baised compound or similar. Effectively i need a small maont of ready mix!!

Help please, it can't be that hard.

 

[Doggit]

Websites tend to give very generic advice, and it tends to need interpreting - preferably with experience. In a cellar wall for instance, you'll get a certain amount of water pressure pushing in from the sides, and it'd get greater as you go down the wall, but in a garage floor, it'll be seeping upwards, so no pressure. If you put down the SLC first, then it's got to be of a type that'll handle moisture, as not all will.

There's lot's of liquid DPMs out there, and as long as you use the sharp sand to provide a key for the SLC, you should be okay. Having looked at the Aquaprufe, I suspect they're recommending 50mm screed, dues to it being bitumen based, and that makes it squidgy, not solid.

 

[kevsterdiy]

Ever build appear the same 50mm minimum on top.

Can you recommend a product or brand that I can use, and suits my and their requirements, all the data sheets I read are the same?

Of course each brand says only use their own products before and after SLC even down to any gaga re floor paint or similar for the final finish. Drives me mad.

 

[Doggit]

I had a damp wall to sort out, and used Safeguard Drybase, and found it was good for floors as well. I phoned tech support, and they told me to use sharp sand for a key, and I've then been using Setcrete SLC from wickes.

 

[kevsterdiy]

Thanks again doggit. That drybase looks good, one of the best you can buy which is why it's expensive. So which setcrete did you use, normal universal or latex?

ie some latex SLC won't work on the chemicals in that drybase or expoxy type.

Setscrete suggest their own primer. Setcrete is made by F.BalI, who also do their own differently numbered/named products.

Once I've added all this up its getting quite expensive all because the builder didn't level the floor properly.

If only I could just prime and add some more ready mix on top and level it (with a timber is good enough like it should have been)!!!

 

[Doggit]

I've been using the Setcrete Latex as it'll go down to 2mm, and Wickes do it at 5 bags for 13.99 each, and it'd gripped to the drybase quite happily - possibly because of the sharp sand trick. I already had the drybase from a previous job, but again, I suspect you could easily use Bostick liquid DPM from Wickes as well.

 

[kevsterdiy]

I've been using the Setcrete Latex as it'll go down to 2mm, and Wickes do it at 5 bags for 13.99 each, and it'd gripped to the drybase quite happily - possibly because of the sharp sand trick. I already had the drybase from a previous job, but again, I suspect you could easily use Bostick liquid DPM from Wickes as well.

Thanks for that.
Maybe the bostick dpm is ok but that's the FAQ I quoted.
I'm quite keen to try the drybase as dpm as you did, then screed with latex SLC and then use the drybase again as a covering as it says on their website. Would mean 3 lots of drybase at nearly £50 a shot.

 

[Doggit]

I'll check their website when I've got some spare time, but you should only need to do 2 coats of Drybase in 1 go, under the SLC, certainly no more than that.

And sorry Kev, missed that we'd already discussed the Bostik, but as I said, sometimes you need to put you're own interpretation on what they're suggesting.

 

[kevsterdiy]

Even 2 costs prior to SLC is a tin and a half (my area is 7m sq) at 4.5msq per tin

Either way the SLC can't be the final finish as I understand it

 

[kevsterdiy]

I have just spoken to f.ball (setcrete) they do not recommend ANY of their SLC range less than 5mm depth in my situation. Even the latex setcrete. They do their own primer then not less than 5mm on top. Even with saying that drybase do a primer he said nope, no dpm means 5mm plus to stand any chance.

Sounds amazed yours has work when I mentioned someone has done it and it worked.

 

[kevsterdiy]

Also just spoke to drybase technical. Yes in terms of paint on and use a dpm with sharp sand as key.
Can't state a advice on SLC products from others, only that 5mm or more sounds better than 2.

Also can't use their dpm as final surface or prior to paint. It repels and water product of course.

So my only option seems gamble on what worked for you Doggit.....