I've asked loads of advice regarding my mouldy kitchen floor.

Thought some may be interested in an update and some techniques I've been
using...

The kitchen (former living room) is about 20m2, old garage knock-through,
floor more than an inch out of true, mostly in small concentrated areas
which meant you could feel it just by walking. Chances of laying tiles on
that (unless they were mosaic) - about zero...

1) Sub job out to builders with simple specification of "please flatten" and
the caveat "is that black tile adhesive residue likely to be a
problem". "Sure" they said "and no, latex screed sticks to everything"...

2)

Get this:

http://photos.dionic.net/v/public/bu..._0002.jpg.html
http://photos.dionic.net/v/public/bu..._0003.jpg.html

Oh dear - still not flat (never mind level) and 3 months later, several
sections were becoming loose. Started investigations on uk.d-i-y and
t'internet.

3) "Develop" a simple height surveying technique based on a Stanley
cross-beam self levelling laser:

http://photos.dionic.net/v/public/bu..._0003.jpg.html

4) Find out that black stuff was "Blackjack" to which nothing sticks, and
cretinous builders used cement/silica gunk and not even latex gunk.

5) SDS up crap and run tungsten tipped flail drum grinder + industrical
vacuum over floor. Based on survey in 3, manage to grind one bay section
down 1cm which brings the whole thing to around 15mm total variation rather
than the 25mm before. Bugger all blackjack left except for odd very small
patches.

Here's the result, after infinite hoovering:

http://photos.dionic.net/v/public/bu..._0024.jpg.html

6) Cut out detatched screed sections - 2m2 by door and couple of other
little bits (sq foot each). Screed is only 2cm thick at best.

7) Notice floor is *incredibly* damp. Notice that 1/2 room (garage bit) has
excellen (if lumpy) screed and other half is made from 99% plastering sand.

8) Soak whole room in 10l SBR + 30l water. Keep going until screed sucks no
more.

9) Get this:

http://photos.dionic.net/v/public/bu..._0001.jpg.html

The brown screed is the crap - but even this is now solid. Cut a bit out and
verify it is solid all the way through. Isn't SBR wonderful!

10) Do a new survey and get this result:

http://photos.dionic.net/v/public/bu...ZPlan.png.html

"0" is the nominal height of the hall floor. +2 means 2mm higher than
hall, -14 means 14mm lower - you get the idea.

11) Write perl program to take this data, and using the volume under a 3D
triangle formula, calculate the volumes of gunk required to take each
vertical strip to a new height - I decided on 2mm above hall floor as this
meant I didn't have to do any more grinding (ignore the +6 - I dealt with
this after that survey).

12) Decide to lay F Ball Stopgap 900 DPM Prep followed by F75 Epoxy DPM,
them primed with P131 and topped with Stopgap 300 based on excellent advice
from here, previous experience with F Ball products and some chats with F
Ball tech. Stopgap 900 is an acrylic compound and withstands damp. It's
primarily designed to act as a smoothing substrate for F75. Unfortunately
F75 must be topped off with something else, and Stopap 300 is a listed
option, so so be it.

13) Stopgap 900 is limited to 15mm (20mm with granite chipping filler).
Infill deep holes with SBR sand cement screed (10-15mm). Mix half bag of
Stopgap 900 + filler and fill small awkward bits - we figure we can bend
the rules a bit...

14) Find out we need 13-14 bags of Stopgap 900. With a working time of 20-30
minutes on a cool day, we are not going to be able to do that in one hit.

Design railing system like this:

http://photos.dionic.net/v/public/bu..._0001.jpg.html
http://photos.dionic.net/v/public/bu..._0004.jpg.html
http://photos.dionic.net/v/public/bu..._0007.jpg.html
http://photos.dionic.net/v/public/bu..._0014.jpg.html

That's ali channel, nice and stiff bolted down to brass studs (cut off
bolts) resin mortared into small 5-10mm deep holes in the floor. There's a
nut (or packing washers) under than channel to set the bottom of the
channel to the required finish height - all down with a 16mm oval conduit
sighting stick and a laser. Masking tape floor and channel, drop channel
on, bolt down, double check with 6' spirit level (all perfect) and floam
seal so gunk cannot escape. Masking tape makes for an easier cleanup of
rail and floor afterwards.

This stage takes about 2 hours per pair of rails (which are butted from
shorter sections for convenience).

The scraper bar is made from the same channel + 2 "ears" of smaller (could
be the same) stuff. The scraper bar inherently scrapes level with the
bottom of the main rails.

15)

Having done a pouring plan based on strips consuming no more than an
estimated 2.5 bags (which always means upto 3 bags due to errors and
wastage), mix a 3 bag batch (with a friend) and pour in. Quick push around
with a float to wet everything and pour some more until 70% is down.

Use scraper bar to pull excess to low areas.

The scraper bar can also be dropped on at random places to spot check the
level - if it *just touches* the gunk, all is good.


Pour more until we have filled the rails evenly. Run over with a spiked
roller (optional) to kick air bubbles out and recheck level with scraper.

Leave for 2 hours and carefull remove rails for reuse.


In theory Stopgap 900 has a 90 minute walk on time. I found it to be rather
longer - it's solid after that time, but not walkable. Probably because my
subfloor is more water resistant due to the SBR than the more usual case
of pouring it directly onto concrete. I bent the rules here, but the first
strip:

http://photos.dionic.net/v/public/bu..._0015.jpg.html
http://photos.dionic.net/v/public/bu..._0017.jpg.html

was as hard as iron the next day, and very well adhered to the SBR so I
judge no ill effects. F Ball won't guarantee this combination but I'm happy
which what I've seen. It's either that or pouring it onto friable crap
which seems a less good idea. If we dig out the firable crap we have vastly
more filling to do and just have to bind it to friable concrete instead. So
we'll call this an "engineering solution".

Lose excess mix in very low spots like this:

http://photos.dionic.net/v/public/bu..._0018.jpg.html



All in all, it took me 1 day to do that strip including cutting the ali,
planning and trying stuff.

Me and a mate did two deep strips yesterday - a lot of the time wasted was
waiting for either PU foam to dry or gunk to be solid enough to go near.

I now have strips A, B and C poured and fingers crossed, they will be level
and mutually at the same height. A certainly checked out to be within 1mm
in any direction.

Now I just have to mix 1 and 2 bag batches and infill, using the current
strips as my guides - so no more rail setup.

Was it worth it?

So far, it looks so. The rails were necessary - Stopgap 900 is less free
flowing than Stopgap 300 so it needed help. Being able to spot check along
the length was invaluable. Knowing I have 3 reference strips that are
correct and flat should lead to a floor with no more than a mm or two error
and that is more than acceptable.

I'll post some more at future stages too.

Cheers

Tim

--
Tim Watts
The ****artist formerly known as Tim S

Owain
wibbled on Monday 21 September 2009 13:22

On 21 Sep, 11:27, Tim W wrote:
Thought some may be interested in an update and some techniques I've been
using...

Jeez oh.

You did check the Mrs doesn't want underfloor heating first though?

Owain

She can did the concrete out if she does!

Yeah - I did consider this. But even with the surface mount UFH products
(www.floorheater.co.uk) I reckoned I'd be passing as much heat into the
ground as I would into the air based on some crude calculations. So that
idea went in the bin fairly early...

--
Tim Watts
The ****artist formerly known as Tim S

Owain
wibbled on Monday 21 September 2009 13:22

On 21 Sep, 11:27, Tim W wrote:
Thought some may be interested in an update and some techniques I've been
using...

Jeez oh.

That about sums it up...

8-|

But I'm rather pleased that it seems to be a viable technique - any other
way of laying that type of screed would be impossible for me to get a
decent result other than perhaps a pump lorry.

Owain
wibbled on Monday 21 September 2009 14:15

On 21 Sep, 13:38, Tim W wrote:
But I'm rather pleased that it seems to be a viable technique -

You'll be able to use it in other rooms in the house then.

Fortunately I don;t have to Other floors are mostly fine (for some
reason).

"Why is it never like this on the telly"

It probably is but:

1) The job in hand might have the budget for a pro to come running in with a
pumped screed truck or an army of people who do this stuff all their lives.

2) The assumed attention span of a viewer (I said assumed) of 1.7 seconds
doesn't play with showing anything more complicated than Beeny's tits so
it's on the editing room floor

3) They bodge it and run away before anyone notices.

I'll go with 3)...

Owain

--
Tim Watts
The ****artist formerly known as Tim S

Owain
wibbled on Monday 21 September 2009 16:54

On 21 Sep, 14:24, Tim W wrote:
2) The assumed attention span of a viewer (I said assumed) of 1.7 seconds
doesn't play with showing anything more complicated than Beeny's tits so
it's on the editing room floor

I read that as "doesn't show anything more complicated than playing
with Beeny's tits"

Rather that than watching Handy Andy get randy with a lump of MDF...

3) They bodge it and run away before anyone notices.
I'll go with 3)...

Exactly, why bother with dpc if you're selling in 8 weeks anyway.

Yeah - I did try that route... Funny how none of the real problems I found
showed up on the gazundering *******s' survey... Except the misted double
glazing pane (oooh surveyers' aren't totally blind at least).

Cheers

Tim

--
Tim Watts
The ****artist formerly known as Tim S

Explaining magnetism to little children:
"The magnet has a boy end and and a girl end and a boy and a girl like to
hold hands. Magnets aren't gay so two boys or two girls push each other
away..."

On Mon, 21 Sep 2009 14:24:27 +0100, Tim W wrote:
3) They bodge it and run away before anyone notices.

I'll go with 3)...

They should make some "DIY SOS SOS" type[1] prog, where a team comes in to
fix the f*ck-ups done by the prior crew who f*cked up fixing the owner's
original f*ck-up.

As a bonus, could be repeated ad-nauseam.

[1] Or even "DIY SOS squared", or maybe "DIY SOS you retarded televisual
******s"

"Tim W" wrote lots!

I had to lay some SLC in the cloakroom last week and that was expensive.
This project must be costing you a fortune, do you have a cheap source of
levelling compound or just a large budget? I would be interested to know as
i have to do our kitchen floor in a few weeks and at £16 per bag in Wickes
it is going to cost more than the tiles!

Tom

Tom
wibbled on Monday 21 September 2009 21:54

"Tim W" wrote lots!

I had to lay some SLC in the cloakroom last week and that was expensive.
This project must be costing you a fortune, do you have a cheap source of
levelling compound or just a large budget? I would be interested to know
as i have to do our kitchen floor in a few weeks and at £16 per bag in
Wickes it is going to cost more than the tiles!

Tom

I get mine from http://yorkflooringsupplies.co.uk/

Yes, it's costing. But it is by my calculation a lot cheaper than paying
someone else to do a full screed - coupled with the fact I no longer trust
builders(!). It would be cheaper to rescreed myself, using an SBR mix, but
having done a couple of little rooms I'd never manage it and I'd have to
level the result anyway.

Your price is pretty much the norm. How did you get on with the cloakroom
and how big is your kitchen? Only asked, because if you wanted a slightly
more fluid compound, I can highly recommend Stopgap 300 which flows like
water - though it's helped by having a primer paint but that's quick and
not expensive.

Cheers

Tim

--
Tim Watts
The ****artist formerly known as Tim S

"Tim W" wrote in message
...
Tom
wibbled on Monday 21 September 2009 21:54

"Tim W" wrote lots!

I had to lay some SLC in the cloakroom last week and that was expensive.
This project must be costing you a fortune, do you have a cheap source of
levelling compound or just a large budget? I would be interested to know
as i have to do our kitchen floor in a few weeks and at £16 per bag in
Wickes it is going to cost more than the tiles!

Tom

I get mine from http://yorkflooringsupplies.co.uk/

Yes, it's costing. But it is by my calculation a lot cheaper than paying
someone else to do a full screed - coupled with the fact I no longer trust
builders(!). It would be cheaper to rescreed myself, using an SBR mix, but
having done a couple of little rooms I'd never manage it and I'd have to
level the result anyway.

Your price is pretty much the norm. How did you get on with the cloakroom
and how big is your kitchen? Only asked, because if you wanted a slightly
more fluid compound, I can highly recommend Stopgap 300 which flows like
water - though it's helped by having a primer paint but that's quick and
not expensive.

Cheers

Tim

--
Tim Watts
The ****artist formerly known as Tim S

I used Wickes High Performance Levelling Compound, i think it has latex
added. I found it surprisingly easy to use, but as with most jobs the worst
part is the prep. It flowed very easily and levelled with a quick flick of
the trowel to guide it into place, but the room is only 2x1m. The kitchen
is 5x3m, lots of prep needed to remove laminate floor, then the old manky
vinyl tiles and the black ****e that is underneath them. My only criticism
of the Wickes stuff is trapped air causing bubbles, i didn't have a spiked
roller so i just knocked the bad ones of with a scrapper prior to tilling
the floor. I'll take a look at stopgap though.

Thanks,

Tom

Tom
wibbled on Monday 21 September 2009 22:21


"Tim W" wrote in message
...
Tom
wibbled on Monday 21 September 2009 21:54

"Tim W" wrote lots!

I had to lay some SLC in the cloakroom last week and that was expensive.
This project must be costing you a fortune, do you have a cheap source
of levelling compound or just a large budget? I would be interested to
know as i have to do our kitchen floor in a few weeks and at £16 per bag
in Wickes it is going to cost more than the tiles!

Tom

I get mine from http://yorkflooringsupplies.co.uk/

Yes, it's costing. But it is by my calculation a lot cheaper than paying
someone else to do a full screed - coupled with the fact I no longer
trust builders(!). It would be cheaper to rescreed myself, using an SBR
mix, but having done a couple of little rooms I'd never manage it and I'd
have to level the result anyway.

Your price is pretty much the norm. How did you get on with the cloakroom
and how big is your kitchen? Only asked, because if you wanted a slightly
more fluid compound, I can highly recommend Stopgap 300 which flows like
water - though it's helped by having a primer paint but that's quick and
not expensive.

Cheers

Tim

--
Tim Watts
The ****artist formerly known as Tim S

I used Wickes High Performance Levelling Compound, i think it has latex
added. I found it surprisingly easy to use, but as with most jobs the
worst part is the prep. It flowed very easily and levelled with a quick
flick of
the trowel to guide it into place,

That sounds quite good.

but the room is only 2x1m. The kitchen
is 5x3m,

That will be harder, unless you do it in sections or can mix a few bags at
once (friend's help will make it easier). Any idea how much avergae depth
you need to apply? Most of that stuff does about 3mm depth over 4-5m2 for a
25kg bag so you'll probably need 4 bags at least.

lots of prep needed to remove laminate floor, then the old manky
vinyl tiles and the black ****e that is underneath them.

Dealing with that black ****e is critical IME. That's what caused the first
lot of crap the builders put down to fail. My black ****e, after further
investigation turned out to almost certainly be a bitumen/ashphaltic type
adhesive, bit like BlackJack.

Do you know if yours is something bituminous?

Do not under any circumstances pour stuff onto that unless you've had sound
advice that your stuff will stick. It shears the bond with heating/cooling
cycles so it may appear to stick, then fall off next week or next year.
When it falls off, large amounts of it go at once.

The plasterer who did some of my skimming told me he'd run into that problem
yonks back before he specialised on plastering on some bunker conversion
job in Germany. In the end, the manufacture prescribed some particular SLC
and instructed that holes must be drilled through the black ****e in a
particular spacing to allow the gunk to get some key. But that sort of
advice sounds highly dependant on the SLC being thick and of a certain
type.

I've heard alternative advice of laying more black ****e (bitumen usually
sticks to more bitumen) and binding with sand then pour onto that. Again,
would only do that on manufacturer's advice.

If you want to get it off, I used a drum scabbler (flail type). It was
fairly quick but it makes an anglegrinder look tame regarding the black
dust storm that will eminate from its bowells.

The other thing that worked for small patches was either a very sharp SDS
chisel or a scutch comb SDS chisel. Relatively little mess and at worst you
leave some black ****e on, but there at least 50% removal in closely spaces
grooves into the screed. I did this round the edges where the machine could
not go.

Sorry if you already have thought it through already - but just some
thoughts.

My only criticism
of the Wickes stuff is trapped air causing bubbles, i didn't have a spiked
roller so i just knocked the bad ones of with a scrapper prior to tilling
the floor. I'll take a look at stopgap though.

Many of the air bubbles are caused by a dry surface under the SLC. I wet any
pourous bist down with water (leaving no standing water) first. The roller
knocks a few bubbles out but I don't get many.

The on place I threw 1/4 bag of leftover down so as not to waste it has
bubbled like crazy due to no wetting. Not bothered, it's going to get
another load on top.

The P131 green neoprene primer that Stopgap 300 requires also helpds
alleviate this problem as it seals the surface.

Regarding your situation, F Ball tech support are very helpful. If you tell
them what you have they may recommend something specific. They are a
cautious bunch though, so they will probably say grind the black ****e off.

Thanks,

Tom

--
Tim Watts
The ****artist formerly known as Tim S