Hi,

One more...

Where the old kitchen's come out, me and the builders have dug out 1" quarry
tiles and there's another inch or so of bedding sand/cement between tiles
and concrete.

Concrete has no damp proof membrane it turns out, though is nice and dry.

Before laying new tiles, how should I screed it? I assume for 50mm,
sand/cement is the stuff to use - but what mix? And is it worth PVA'ing the
concrete or painting on a liquid DPC membrane? I'm going to use some paint
on membrane in the wetroom shower anyway.

Many thanks,

Tim

50mm is quite thin for a semi-dry screed ...
If it were me I'd use a fibre reinforced screed .... you can own mix, a 4:1
mix would be OK, buy buying bags of the fibres to add to the mix ... FIBRIN
is one well know make.

If it is not a huge area you could use liquid self leveling screed, but
pricey if a big area.



Problem will be if you p
"Tim S" wrote in message
...
Hi,

One more...

Where the old kitchen's come out, me and the builders have dug out 1"
quarry
tiles and there's another inch or so of bedding sand/cement between tiles
and concrete.

Concrete has no damp proof membrane it turns out, though is nice and dry.

Before laying new tiles, how should I screed it? I assume for 50mm,
sand/cement is the stuff to use - but what mix? And is it worth PVA'ing
the
concrete or painting on a liquid DPC membrane? I'm going to use some paint
on membrane in the wetroom shower anyway.

Many thanks,

Tim

Tim S wrote:

Where the old kitchen's come out, me and the builders have dug out 1" quarry
tiles and there's another inch or so of bedding sand/cement between tiles
and concrete.

Concrete has no damp proof membrane it turns out, though is nice and dry.

Before laying new tiles, how should I screed it? I assume for 50mm,
sand/cement is the stuff to use - but what mix? And is it worth PVA'ing the
concrete or painting on a liquid DPC membrane? I'm going to use some paint
on membrane in the wetroom shower anyway.

I would go with a paint on DPC just to be sure, and then a fairly strong
mix (4:1) sharp sand / cement screed to make up the 50mm. Possibly with
a latex self levelling to get a nice finish on the last couple of mm
(depends on how neat your screeding turns out).

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm coughed up some electrons that declared:

Tim S wrote:

Where the old kitchen's come out, me and the builders have dug out 1"
quarry tiles and there's another inch or so of bedding sand/cement
between tiles and concrete.

Concrete has no damp proof membrane it turns out, though is nice and dry.

Before laying new tiles, how should I screed it? I assume for 50mm,
sand/cement is the stuff to use - but what mix? And is it worth PVA'ing
the concrete or painting on a liquid DPC membrane? I'm going to use some
paint on membrane in the wetroom shower anyway.

I would go with a paint on DPC just to be sure, and then a fairly strong
mix (4:1) sharp sand / cement screed to make up the 50mm. Possibly with
a latex self levelling to get a nice finish on the last couple of mm
(depends on how neat your screeding turns out).


Thanks John, Rick.

Now that the builders have cut the old bedding off, back to the concrete, I
see that I have only about 35mm depth - bedding was less thick than I
thought.

Most of it is very stable except for a few patches round the edges. Do you
reckon I'll still be OK with sand/cement on top of a painted membrane or
should I be looking at something like:


http://filesdown.esecure.co.uk/wykam...07-1312-21.pdf

[Technocryl 2001]

It looks good but at 85 per 25l it's not cheap.

The final finish isn't critical - it's going to get more floor tiles (stone
or ceramic) stuck on, so mostly flat and stable is the main aim.

Cheers

Tim

On 2 Dec, 13:19, Tim S wrote:
John Rumm coughed up some electrons that declared:





Tim S wrote:

Where the old kitchen's come out, me and the builders have dug out 1"
quarry tiles and there's another inch or so of bedding sand/cement
between tiles and concrete.

Concrete has no damp proof membrane it turns out, though is nice and dry.

Before laying new tiles, how should I screed it? I assume for 50mm,
sand/cement is the stuff to use - but what mix? And is it worth PVA'ing
the concrete or painting on a liquid DPC membrane? I'm going to use some
paint on membrane in the wetroom shower anyway.

I would go with a paint on DPC just to be sure, and then a fairly strong
mix (4:1) sharp sand / cement screed to make up the 50mm. Possibly with
a latex self levelling to get a nice finish on the last couple of mm
(depends on how neat your screeding turns out).

Thanks John, Rick.

Now that the builders have cut the old bedding off, back to the concrete, I
see that I have only about 35mm depth - bedding was less thick than I
thought.

Most of it is very stable except for a few patches round the edges. Do you
reckon I'll still be OK with sand/cement on top of a painted membrane or
should I be looking at something like:

http://filesdown.esecure.co.uk/wykam...df_10072007-13...

[Technocryl 2001]

It looks good but at 85 per 25l it's not cheap.

The final finish isn't critical - it's going to get more floor tiles (stone
or ceramic) stuck on, so mostly flat and stable is the main aim.

Cheers

Tim- Hide quoted text -

- Show quoted text -

That's too thin for unmodified cement/sand screed, so yes, you need to
polymer modify it (ought to be able to get SBR a bit cheaper than
£85/25l if you shop around), or else you are in range of the higher-
build 'self-levellers' (again, at a price).

coughed up some electrons that declared:

On 2 Dec, 13:19, Tim S wrote:

Thanks John, Rick.

Now that the builders have cut the old bedding off, back to the concrete,
I see that I have only about 35mm depth - bedding was less thick than I
thought.

Most of it is very stable except for a few patches round the edges. Do
you reckon I'll still be OK with sand/cement on top of a painted membrane
or should I be looking at something like:

http://filesdown.esecure.co.uk/wykam...df_10072007-13...

[Technocryl 2001]

It looks good but at 85 per 25l it's not cheap.

The final finish isn't critical - it's going to get more floor tiles
(stone or ceramic) stuck on, so mostly flat and stable is the main aim.

Cheers

Tim- Hide quoted text -

- Show quoted text -

That's too thin for unmodified cement/sand screed, so yes, you need to
polymer modify it (ought to be able to get SBR a bit cheaper than
£85/25l if you shop around), or else you are in range of the higher-
build 'self-levellers' (again, at a price).

Thanks for that. By "SBR" do you mean something like Everbuild 503, eg:

http://www.u-diy.co.uk/index.aspx?s=Product&p=601

?

Cheers

Tim

On 2 Dec, 15:42, Tim S wrote:
coughed up some electrons that declared:





On 2 Dec, 13:19, Tim S wrote:
Thanks John, Rick.

Now that the builders have cut the old bedding off, back to the concrete,
I see that I have only about 35mm depth - bedding was less thick than I
thought.

Most of it is very stable except for a few patches round the edges. Do
you reckon I'll still be OK with sand/cement on top of a painted membrane
or should I be looking at something like:

http://filesdown.esecure.co.uk/wykam...df_10072007-13....

[Technocryl 2001]

It looks good but at 85 per 25l it's not cheap.

The final finish isn't critical - it's going to get more floor tiles
(stone or ceramic) stuck on, so mostly flat and stable is the main aim..

Cheers

Tim- Hide quoted text -

- Show quoted text -

That's too thin for unmodified cement/sand screed, so yes, you need to
polymer modify it (ought to be able to get SBR a bit cheaper than
£85/25l if you shop around), or else you are in range of the higher-
build 'self-levellers' (again, at a price).

Thanks for that. By "SBR" do you mean something like Everbuild 503, eg:

http://www.u-diy.co.uk/index.aspx?s=Product&p=601

Yep, that's an SBR. Basically a latex admixture. Not sure how it
would stick to a chemical dpm, the self-levelling manufacturers (not
that different) get very fussy about which of their products can be
used over chemical dpms.

Here's some handy instructions: http://constructionchemicals.co.uk/a...brcomplete.pdf

Tim S wrote:
John Rumm coughed up some electrons that declared:

Tim S wrote:

Where the old kitchen's come out, me and the builders have dug out 1"
quarry tiles and there's another inch or so of bedding sand/cement
between tiles and concrete.

Concrete has no damp proof membrane it turns out, though is nice and dry.

Before laying new tiles, how should I screed it? I assume for 50mm,
sand/cement is the stuff to use - but what mix? And is it worth PVA'ing
the concrete or painting on a liquid DPC membrane? I'm going to use some
paint on membrane in the wetroom shower anyway.
I would go with a paint on DPC just to be sure, and then a fairly strong
mix (4:1) sharp sand / cement screed to make up the 50mm. Possibly with
a latex self levelling to get a nice finish on the last couple of mm
(depends on how neat your screeding turns out).


Thanks John, Rick.

Now that the builders have cut the old bedding off, back to the concrete, I
see that I have only about 35mm depth - bedding was less thick than I
thought.

Most of it is very stable except for a few patches round the edges. Do you
reckon I'll still be OK with sand/cement on top of a painted membrane or
should I be looking at something like:

I would say that is too thin for a screed over something flexible. (i.e.
over an insulation board). However, onto a concrete base I can't see you
having a problem with a thinner screed.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Hi,

On a related note, I noticed that one of the screed admixes said not to use
a cement mixer as air entrapment could be a problem.

Would one of these in my Aldi SDS be right for the job, in a suitably large
tub?

http://www.screwfix.com/prods/98121/...rtar-Mixer-M14

(Obviously with the M14-SDS adaptor).

Cheers

Tim

Tim S wrote:
Hi,

On a related note, I noticed that one of the screed admixes said not to use
a cement mixer as air entrapment could be a problem.

Would one of these in my Aldi SDS be right for the job, in a suitably large
tub?

http://www.screwfix.com/prods/98121/...rtar-Mixer-M14

(Obviously with the M14-SDS adaptor).

Cheers

Tim

Mixers run at 250-580rpm, and are built for the purpose. I don't think
your sds motor would survive the experience.

stuart noble coughed up some electrons that declared:

Tim S wrote:
Hi,

On a related note, I noticed that one of the screed admixes said not to
use a cement mixer as air entrapment could be a problem.

Would one of these in my Aldi SDS be right for the job, in a suitably
large tub?


http://www.screwfix.com/prods/98121/...rtar-Mixer-M14

(Obviously with the M14-SDS adaptor).

Cheers

Tim

Mixers run at 250-580rpm, and are built for the purpose. I don't think
your sds motor would survive the experience.

So these things are more aimed at plaster then?

Is it OK to hand mix screed in the traditional way, even with an admix?

Cheers

Tim

Tim S wrote:
stuart noble coughed up some electrons that declared:

Tim S wrote:
Hi,

On a related note, I noticed that one of the screed admixes said not to
use a cement mixer as air entrapment could be a problem.

Would one of these in my Aldi SDS be right for the job, in a suitably
large tub?


http://www.screwfix.com/prods/98121/...rtar-Mixer-M14
(Obviously with the M14-SDS adaptor).

Cheers

Tim
Mixers run at 250-580rpm, and are built for the purpose. I don't think
your sds motor would survive the experience.

So these things are more aimed at plaster then?

They're for the Makita mixers I think, or something equally beefy.
Plaster is worse in some ways because it can suddenly thicken and put a
hell of a strain on the motor

Is it OK to hand mix screed in the traditional way, even with an admix?

If you're talking about the 2 part latex screed, the solids don't absorb
the liquid as cement would, so I don't think thorough mixing is
crucial, but "screed" can mean pretty much anything.

stuart noble coughed up some electrons that declared:


They're for the Makita mixers I think, or something equally beefy.
Plaster is worse in some ways because it can suddenly thicken and put a
hell of a strain on the motor

Is it OK to hand mix screed in the traditional way, even with an admix?

If you're talking about the 2 part latex screed, the solids don't absorb
the liquid as cement would, so I don't think thorough mixing is
crucial, but "screed" can mean pretty much anything.

I was thinking mostly about sand/cement + admix. I would have chucked this
stuff in a regular mixer, but the admix instructions on at least one admix
say not to do that as too much air gets entrained.

Cheers

Tim

stuart noble wrote:

If you're talking about the 2 part latex screed, the solids don't absorb
the liquid as cement would, so I don't think thorough mixing is
crucial, but "screed" can mean pretty much anything.

When I do the latex cement (water mix type from Wickes), I stick the
required 5L in a big mixing bucket, tip in the bag of powder and just
use a medium sized paddle in my 18V combi drill. Works very well I find.
(I do plaster in the same way). It would not cope with large mixes of
mortar though.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Tim S wrote:

Would one of these in my Aldi SDS be right for the job, in a suitably large
tub?

http://www.screwfix.com/prods/98121/.../Makita-Mortar
-Mixer-M14

(Obviously with the M14-SDS adaptor).

I used one of the other mixers (the £5 job) for mixing up two-part
felxible tile cement. I didn't use the SDS, I used a Bosch "blue" drill
with a two-speed gearbox running at 300rpm. It seemed to do a decent job
without any problems.

Tim S coughed up some electrons that declared:

Hi,

One more...

Where the old kitchen's come out, me and the builders have dug out 1"
quarry tiles and there's another inch or so of bedding sand/cement between
tiles and concrete.

Concrete has no damp proof membrane it turns out, though is nice and dry.

Before laying new tiles, how should I screed it? I assume for 50mm,
sand/cement is the stuff to use - but what mix? And is it worth PVA'ing
the concrete or painting on a liquid DPC membrane? I'm going to use some
paint on membrane in the wetroom shower anyway.

Many thanks,

Tim

Thanks for all the replies.

Been looking at the grand budget spreadsheet today and decided time for
extravagance needs to be over or costs will go the way of a government
contract!

Think I'll get a paddle for the SDS on the basis that it'll mix plaster and
tile gloop (need lots of both and it's a cheap Aldi grunt drill so I don't
mind abusing it).

If it can cope with cement screed, well and good, otherwise I'll mix by
hand, the old fashioned way... If nothing else, it'll turn the dry mix over
OK which is half the work...

Cheers

Tim