Tim S wibbled:

Question:

What (bloody big) machine do I look for in the hire shop that will scrape,
in a violent and deadly fashion, the top couple of mm off a strong
sand/cement screed? Thinking something with carbide teeth that move about,
and a feck off big motor or petrol engine.

Got quite a large area to do. If the machine can hack its way through not
well attached cement levelling compound, all the better.

Ta

Tim


[The scenario...]

Not a happy bunny today...

The long saga of dealing with the crap that is my new kitchen floor:

Previously, on Planet Squidward:

1) I asked builders to flatten a lumpy floor. I took a load of old wooden
tiles up for them.

2) I asked if they would deal with the residual gunk under the tiles. "No
- it's not a problem - Latex gunk sticks to anything..."

3) 3 months ago, I noticed a couple of hollow sounding bits.

4) I noticed they been fobbed off with Cement/silica (Cempolay) rather
than latex (Cempolatex) by the tit in Travis Perkins.

----

Back to today:

"I know," I said - "I'll just angle grind the loose bits - quick run tound
the edge with a diamond blade - then pop the loose bit out, then repair
taht bit ready for pouring more latex this week"...

I did, and a couple of whacks with a hand bolster and the Cempolay was
coming up in 6-8mm sheets. Oh dear.

Went round and sounded the rest of teh floor. Now about 6-7 loose areas.
The bond has been shearing all overthe place.

When I looked at the layer that popped up, it contained a mm thick black
slightly greasy/rubbery/slippery (to the nail) brittle black layer of
crap.

Underneath that, the sand/cement screed appears very solid and attached -
but well out of level.

I've checked into this black crap and believe it may be an asphaltic
adhesive used on wood flooring.

It's impossible to totally remove it without taking the top mm of screed
with it. Tried a big knife - no good. Scutch comb works but will take
forever. So I'm off to the hire shop tomorrow - just wanted to have a bit
more of a clue what to ask for.

Follow up:

Hired something like one of these (in the 110V, not petrol):

http://www.brandontoolhire.co.uk/dir...?idproduct=459

(at half that price - we like our small local hire shop

It has a drum like this on:

http://www.homedepot.com/catalog/pro...6d155a_400.jpg

It's noisy, it produces more dust than even an angle grinder (though heavier
so it does settle down quicker).

But it does certainly work! We took about 95% of the asphalt crap off -
small trace patches left only and a strip round the edge where the machine
can't go. Strip round edge dealt with with a very sharp wide SDS chisel.

Machine made light work of thin old cement levelling compound - asphalt crap
took several passes but it was a pretty painless exercise and well worth
the 45 quid + VAT hire.

It was powerful enough to grind down 1cm off a high area in fairly hard
screed too.

The finish is generally flat with slight grooving. I don't see any problems
now in getting a good key for the next layer.

I did try it on the hall to see how subtle it could be on rubbery glue
residue on screed - answer - with careful control of the height knob, it is
subtle enough to scratch that off without major damage to the screed.

In the end, the hire time was expiring and I decided the very thin and non
asphaltic glue residue in the hall and other rooms was unlikely to be a
serious problem to applying floor tiles etc, so I didn't bother doing
those. If faced with that alone, something with a wire brush on would
probably be better.



Called the original builder back anyway, as an 8" wide columb of celcon
blocks holding up a door lintle are parting company with the brick wall
they are supposed to be extending.


Re-did this too. Once the acro prop was in it took all of hand effort to
remove the old blocks. The so called tying in to the old wall consisted of
exactly 2 screws protruding into the new mortar courses.

Pathetic...

I cut out some of the screed down to concrete to give a good seating to the
bottom brick, soaked the concrete in SBR twice to aid in water resistance
and primed with cement/SBR to give a good bond.

Every 1/2 brick in the end of the old wall was previously removed with an
angle grinder and SDS and the mortar cleaned off, including any exposed
frogs.

Did a new column in brick and a 3:1 sand/cement mortar (normally too strong
for regular brickwork but it's my standard for repair work like this). All
new bricks were soaked in a bucket of water and the the old brickwork
sprayed twice with a garden sprayer. I aimed for zero suckage.

Where possible new bricks were oriented so that new frog was adjacent to old
frog to give an extra mechanical bond.

Mortar was packed in medium wet until every joint was solid.

Acro came out the next morning and the brickwork is most certainly not going
anywhere... Very pleasing result... I will wager it will stand a club
hammer if allowed to cure for a week or so...

Cheers

Tim