From Newsgroup: uk.d-i-y

I live in a mid-terrace house on a bend in the road. What's that got
to do with anything? Well, the back wall is noticeably wider than the
front wall and none of the walls are actually square in the corners. Consequently, the shower tray fits snugly into its corner but with one
side right up against its wall and the other with a gap behind which
ranges from zero to about 15mm. With the tile overhang that narrows to
about 7mm at the far edge. Water resistance previously came from the
shower base trim which covered over that gap.

Only it's not water resistant any more. I think the grout between the
tiles has become porous too.

I've stripped out everything except the tiles which seem well fixed
and in good condition. I'm in the process of regrouting them now.

The quadrant shower enclosure (now stripped out) was obviously
installed by a cowboy (probably the previous homeowner) who obviously
felt that there was nothing some extra sealant couldn't cure - except
it obviously wasn't curing the way one quadrant enclosure upright
overhung the back of the shower tray and had a tendency to drip water
into the gap between the tray and the wall.

My plan is to fill the wedge-shaped void behind the shower tray with
cement, leveled off so that it becomes an extension of the shower tray
profile and water running down inside the upright will run into tray
as it ought to. Good idea? Bad idea?

Should I seal the surface of the cement in any way or will its natural
water resistance be enough? I plan to seal the gap between the tiles
and the tray with quadrant beading sealed with silicone so the only
exposed cement will be behind the upright.

How could I do this better?

Thanks,

Nick
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 02/10/2025 07:28, Nick Odell wrote:

I live in a mid-terrace house on a bend in the road. What's that got
to do with anything? Well, the back wall is noticeably wider than the
front wall and none of the walls are actually square in the corners. Consequently, the shower tray fits snugly into its corner but with one
side right up against its wall and the other with a gap behind which
ranges from zero to about 15mm. With the tile overhang that narrows to
about 7mm at the far edge. Water resistance previously came from the
shower base trim which covered over that gap.

Only it's not water resistant any more. I think the grout between the
tiles has become porous too.

I've stripped out everything except the tiles which seem well fixed
and in good condition. I'm in the process of regrouting them now.

The quadrant shower enclosure (now stripped out) was obviously
installed by a cowboy (probably the previous homeowner) who obviously
felt that there was nothing some extra sealant couldn't cure - except
it obviously wasn't curing the way one quadrant enclosure upright
overhung the back of the shower tray and had a tendency to drip water
into the gap between the tray and the wall.

If it's been doing that for some time, are you sure that the floorboards
under the shower aren't rotting through? And if it's right at the edge
of the wall, the joists might be checking too.

It would really be worth looking at any wood before doing any remedial work.
> My plan is to fill the wedge-shaped void behind the shower tray with

cement, leveled off so that it becomes an extension of the shower tray profile and water running down inside the upright will run into tray
as it ought to. Good idea? Bad idea?

Should I seal the surface of the cement in any way or will its natural
water resistance be enough? I plan to seal the gap between the tiles
and the tray with quadrant beading sealed with silicone so the only
exposed cement will be behind the upright.

How could I do this better?

Concrete is not waterproof unless specifically treated. Why not use a waterproof expanding polyurethane foam? Many examples here: <https://www.amazon.co.uk/waterproof-expanding-foam/s?k=waterproof+expanding+foam>

Then perhaps use a sink trim all round, although it depends on how deep
the grout is between the tiles. A little extra sealant to fill any gaps
might be required.
<https://www.amazon.co.uk/sink-trim/s?k=sink+trim>
--
Jeff
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

Jeff Layman <Jeff@invalid.invalid> wrote:

Concrete is not waterproof unless specifically treated. Why not use a waterproof expanding polyurethane foam? Many examples here: <https://www.amazon.co.uk/waterproof-expanding-foam/s?k=waterproof+expanding+foam>

For the record, most expanding foams are open cell and allow moisture
through. Many of the search results on that term aren't actually waterproof (some are 'weatherproof' - not sure what that means but likely not
serious quantities of spray), so check your results carefully.

I recently ordered a can of this (at -u15 a can, not what they're currently charging): https://www.solseal.co.uk/building-products/foams-and-ancillaries/sika-boom-405-water-stop-expanding-foam-320ml/

which is a closed cell foam specifically designed for waterproofing. I
haven't used it yet.

Theo
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 02/10/2025 07:28, Nick Odell wrote:

My plan is to fill the wedge-shaped void behind the shower tray with
cement, leveled off so that it becomes an extension of the shower tray profile and water running down inside the upright will run into tray
as it ought to. Good idea? Bad idea?

What I did, and it seems to be holding so far., when my bathe ledge
developed a leak was to go and get some Celotex from Wickes, and some
foaming gorilla glue. I could have used a can of expanding foam I
guess...and cut the Celotex to fit the gap and glued it all in place
with the foaming gorilla. This sealed the gap and was flexible enough
not to crack when the bath was full of me and water.

But I ran some flexible caulk down the seams just in case and replaced
the tiles over it.

The solid grout has cracked slightly after the first path use, but no
water has got through at all.

By all means then add a decorative layter over the top - I already had
tiles.

Should I seal the surface of the cement in any way or will its natural
water resistance be enough?

I really wouldn't use cement - too brittle - will crack - but a strong
mix of about 2 sand to one cemet is pretty much 100% waterproof since
the cement fills all the gaps between the sand grains

I plan to seal the gap between the tiles
and the tray with quadrant beading sealed with silicone so the only
exposed cement will be behind the upright.

How could I do this better?

My technique, adopted all over four bathrooms I built in this house is
to use slightly flexible gap sealing and waterproofing and then add
decorative tiling on top.
So I seal the appliance edge to the wall/floor/whatever with silicone
BEFORE adding the tiling.

Concrete an mortar is simply to rigid. Hence my advice to use something
more flexible like expanding foam if you can bear the mess, or something
else that is waterproof sealed in place with foaming glue.

I really dislike beading and silicone on show. My ideal is to get the waterproofing and structural work done and then add decoration and not
have to worry about e,g. tile grout cracking slightly.
--
rCLwhen things get difficult you just have to lierCY

rCo Jean Claud J|+ncker

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

Theo <theom+news@chiark.greenend.org.uk> wrote:

Jeff Layman <Jeff@invalid.invalid> wrote:

Concrete is not waterproof unless specifically treated. Why not use a waterproof expanding polyurethane foam? Many examples here: <https://www.amazon.co.uk/waterproof-expanding-foam/s?k=waterproof+expanding+foam>

For the record, most expanding foams are open cell and allow moisture through. Many of the search results on that term aren't actually waterproof (some are 'weatherproof' - not sure what that means but likely not
serious quantities of spray), so check your results carefully.

I recently ordered a can of this (at -u15 a can, not what they're currently charging): https://www.solseal.co.uk/building-products/foams-and-ancillaries/sika-boom-405-water-stop-expanding-foam-320ml/

which is a closed cell foam specifically designed for waterproofing. I haven't used it yet.

A test of water absorption of various spray foams, conclusions inconclusive
but the closed cell pond foam worked out a bit better: https://www.youtube.com/watch?v=P0vcxtCDYTs
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 02/10/2025 10:45, Theo wrote:

Jeff Layman <Jeff@invalid.invalid> wrote:

Concrete is not waterproof unless specifically treated. Why not use a
waterproof expanding polyurethane foam? Many examples here:
<https://www.amazon.co.uk/waterproof-expanding-foam/s?k=waterproof+expanding+foam>

For the record, most expanding foams are open cell and allow moisture through. Many of the search results on that term aren't actually waterproof (some are 'weatherproof' - not sure what that means but likely not
serious quantities of spray), so check your results carefully.

I recently ordered a can of this (at -u15 a can, not what they're currently charging): https://www.solseal.co.uk/building-products/foams-and-ancillaries/sika-boom-405-water-stop-expanding-foam-320ml/

which is a closed cell foam specifically designed for waterproofing. I haven't used it yet.

Theo

Even if what you say is true, a shower enclosure is no worse than e.g. a window cill in the rain etc.

But I think most foam is closed cell, or it wouldn't expand, would it?
--
Any fool can believe in principles - and most of them do!



--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 02/10/2025 11:26, Theo wrote:

Theo <theom+news@chiark.greenend.org.uk> wrote:

Jeff Layman <Jeff@invalid.invalid> wrote:

Concrete is not waterproof unless specifically treated. Why not use a
waterproof expanding polyurethane foam? Many examples here:
<https://www.amazon.co.uk/waterproof-expanding-foam/s?k=waterproof+expanding+foam>

For the record, most expanding foams are open cell and allow moisture
through. Many of the search results on that term aren't actually waterproof >> (some are 'weatherproof' - not sure what that means but likely not
serious quantities of spray), so check your results carefully.

I recently ordered a can of this (at -u15 a can, not what they're currently >> charging):
https://www.solseal.co.uk/building-products/foams-and-ancillaries/sika-boom-405-water-stop-expanding-foam-320ml/

which is a closed cell foam specifically designed for waterproofing. I
haven't used it yet.

A test of water absorption of various spray foams, conclusions inconclusive but the closed cell pond foam worked out a bit better: https://www.youtube.com/watch?v=P0vcxtCDYTs

I wonder why canoes full of it don't sink then.

I suspect yer man here is a bit of a twat, trying to make a videos about nothing
--
rCLIt is dangerous to be right in matters on which the established
authorities are wrong.rCY

rCo Voltaire, The Age of Louis XIV

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

The Natural Philosopher <tnp@invalid.invalid> wrote:

On 02/10/2025 10:45, Theo wrote:

Jeff Layman <Jeff@invalid.invalid> wrote:

Concrete is not waterproof unless specifically treated. Why not use a
waterproof expanding polyurethane foam? Many examples here:
<https://www.amazon.co.uk/waterproof-expanding-foam/s?k=waterproof+expanding+foam>

For the record, most expanding foams are open cell and allow moisture through. Many of the search results on that term aren't actually waterproof
(some are 'weatherproof' - not sure what that means but likely not
serious quantities of spray), so check your results carefully.

I recently ordered a can of this (at -u15 a can, not what they're currently charging): https://www.solseal.co.uk/building-products/foams-and-ancillaries/sika-boom-405-water-stop-expanding-foam-320ml/

which is a closed cell foam specifically designed for waterproofing. I haven't used it yet.

Theo

Even if what you say is true, a shower enclosure is no worse than e.g. a window cill in the rain etc.

It's much more humid and receives less wind to dry it, and open cell foam
works like a sponge to collect and transfer moisture. It needs a flow of
air to dry, which is something a window cill doesn't lack but you aren't
likely to find behind the wall in a poorly ventilated bathroom.

But I think most foam is closed cell, or it wouldn't expand, would it?

No, the cell structure is whether the voids are separate or connected. A plastic dish sponge is open cell in that the water can travel between the voids, even though the plastic itself is not permeable. If you dunk a
sponge in water it'll soak it up, if you dunk a piece of expanded
polystyrene (closed cell) it'll float and not absorb water.

Of course, there's no such thing as 100% open or 100% closed cell and the
void size varies, so open cell spray foams don't soak up water anywhere near
as readily as a sponge - but they still let moisture through and aren't waterproof.

Seems that most one-part foams (ie what you get in a can) are open cell, and two part foams (where they're mixed in the spray gun) are
closed cell. But a lot of the foams available in the UK don't actually say, and two-part foams are relatively rare.

(Soudafoam 2K is a cheaper 2-part one, datasheet says it's 81% closed cell)

Theo
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 02/10/2025 11:49, The Natural Philosopher wrote:

But I think most foam is closed cell, or it wouldn't expand, would it?

The stuff that your local energy advisor wanted to spray on your roof to replace the old style fibreglass loft insulation, and then make it
impossible to get home insurance, was probably open cell.

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

Nick Finnigan <nix@genie.co.uk> wrote:

On 02/10/2025 11:49, The Natural Philosopher wrote:

But I think most foam is closed cell, or it wouldn't expand, would it?

The stuff that your local energy advisor wanted to spray on your roof to replace the old style fibreglass loft insulation, and then make it impossible to get home insurance, was probably open cell.

Indeed - it absorbs and holds moisture against the timbers so they rot.

PIR foam board (celotex etc) is closed cell so it doesn't do that.

Theo
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 02/10/2025 07:28, Nick Odell wrote:

Should I seal the surface of the cement in any way or will its natural
water resistance be enough? I plan to seal the gap between the tiles
and the tray with quadrant beading sealed with silicone so the only
exposed cement will be behind the upright.

How could I do this better?

For you final sealant consider CT1 (toolstaion etc.)

https://www.youtube.com/watch?v=Fd8Mqe18cAU
--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

alan_m wrote:

For you final sealant consider CT1-a (toolstaion etc.)

I've used it and it is impressive stuff, but they used to market it as
"the only sealant you'll ever need" but now they seem to be marketing
half a dozen different sealants for different jobs ...
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

Andy Burns <usenet@andyburns.uk> wrote:

alan_m wrote:

For you final sealant consider CT1-a (toolstaion etc.)

I've used it and it is impressive stuff, but they used to market it as
"the only sealant you'll ever need" but now they seem to be marketing
half a dozen different sealants for different jobs ...

They market it as 'even works under water', but when did you ever need to
apply sealant under water?

SF have a clone called OB1:
https://www.screwfix.com/brand/ob1

that seems to do the same things and is cheaper.

Theo
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

Theo <theom+news@chiark.greenend.org.uk> wrote:

Andy Burns <usenet@andyburns.uk> wrote:

alan_m wrote:

For you final sealant consider CT1-a (toolstaion etc.)

I've used it and it is impressive stuff, but they used to market it as "the only sealant you'll ever need" but now they seem to be marketing
half a dozen different sealants for different jobs ...

They market it as 'even works under water', but when did you ever need to apply sealant under water?

Quite often if you're tying to stop a window leaking for example.
--
Chris Green
-+
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

Chris Green wrote:

Theo wrote:

They market it as 'even works under water', but when did you ever need to
apply sealant under water?

Quite often if you're tying to stop a window leaking for example.

While something is wet sure. But IIRC they showed it sticking two
breeze blocks together while submerged in a fish-tank.
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 02/10/2025 08:08, Jeff Layman wrote:

Concrete is not waterproof unless specifically treated.

I have never tried it myself, so I am just throwing the idea out here
for others to comment on:
Would mixing PVA into the cement make it waterproof permanently after
drying?


--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 03/10/2025 10:05, Indy Jess John wrote:

On 02/10/2025 08:08, Jeff Layman wrote:

Concrete is not waterproof unless specifically treated.

I have never tried it myself, so I am just throwing the idea out here
for others to comment on:
Would mixing PVA into the cement make it waterproof permanently after drying?

I have found it waterproof if enough cement is used to fill the gaps
between the sand. I am sure other things would work as well, possibly at
a cheaper price.


--
Civilization exists by geological consent, subject to change without notice.
rCo Will Durant

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 3 Oct 2025 at 10:05:14 BST, Indy Jess John wrote:

On 02/10/2025 08:08, Jeff Layman wrote:

Concrete is not waterproof unless specifically treated.

I have never tried it myself, so I am just throwing the idea out here
for others to comment on:
Would mixing PVA into the cement make it waterproof permanently after
drying?

Not sure, but I'd guess it wasn't necessary for the construction of concrete ships. Just a strong concrete mix I'd have thought, 3 sand:1 concrete or some such.
--
Cheers, Rob, Sheffield UK
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

RJH <patchmoney@gmx.com> wrote:

On 3 Oct 2025 at 10:05:14 BST, Indy Jess John wrote:

On 02/10/2025 08:08, Jeff Layman wrote:

Concrete is not waterproof unless specifically treated.

I have never tried it myself, so I am just throwing the idea out here
for others to comment on:
Would mixing PVA into the cement make it waterproof permanently after
drying?

Not sure, but I'd guess it wasn't necessary for the construction of concrete ships. Just a strong concrete mix I'd have thought, 3 sand:1 concrete or some such.

PVA tends to re-emulsify when wet so I cannot see it making concrete waterproof. You can get waterproofing additives to mix into mortar that
work well the only issue is for a small job it will be rather expensive. I
can attest to the additives waterproofing as my timber garage sits on a
single brick foundation on the concrete base. The groundworkrCOs people who prepared the base used waterproofing additive in the mortar and there has
not been the slightest bit of damp let alone water penetrating.

Richard
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On Thu, 2 Oct 2025 13:39:21 +0100, alan_m <junk@admac.myzen.co.uk>
wrote:

On 02/10/2025 07:28, Nick Odell wrote:

Should I seal the surface of the cement in any way or will its natural
water resistance be enough? I plan to seal the gap between the tiles
and the tray with quadrant beading sealed with silicone so the only
exposed cement will be behind the upright.

How could I do this better?

For you final sealant consider CT1 (toolstaion etc.)

https://www.youtube.com/watch?v=Fd8Mqe18cAU

That looks seriously interesting stuff. Way more expensive than
anything else I've ever used before but probably well worth it.

Thanks,

Nick
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 02 Oct 2025 15:55:12 +0100 (BST), Theo
<theom+news@chiark.greenend.org.uk> wrote:

Andy Burns <usenet@andyburns.uk> wrote:

alan_m wrote:

For you final sealant consider CT1a (toolstaion etc.)

I've used it and it is impressive stuff, but they used to market it as
"the only sealant you'll ever need" but now they seem to be marketing
half a dozen different sealants for different jobs ...

They market it as 'even works under water', but when did you ever need to >apply sealant under water?

The "even works under water" claim never did Milliput any harm. Er...
has anybody actually seen any Milliput recently?

SF have a clone called OB1:
https://www.screwfix.com/brand/ob1

that seems to do the same things and is cheaper.

OB1? Shouldn't the company be called Star Wars, not Screw Fix?


Nick
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On Fri, 3 Oct 2025 09:29:37 -0000 (UTC), RJH <patchmoney@gmx.com>
wrote:

On 3 Oct 2025 at 10:05:14 BST, Indy Jess John wrote:

On 02/10/2025 08:08, Jeff Layman wrote:

Concrete is not waterproof unless specifically treated.

I have never tried it myself, so I am just throwing the idea out here
for others to comment on:
Would mixing PVA into the cement make it waterproof permanently after
drying?

Not sure, but I'd guess it wasn't necessary for the construction of concrete >ships. Just a strong concrete mix I'd have thought, 3 sand:1 concrete or some >such.

You've just given me an idea. Forget the cement: all I need are some
pulped-up copies of Metro and a giant freezer plant and I could make
my own shower-room version of Project Habakkuk instead!

Nick
https://en.wikipedia.org/wiki/Project_Habakkuk
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

Nick Odell wrote:

alan_m wrote:

For you final sealant consider CT1

That looks seriously interesting stuff. Way more expensive than
anything else I've ever used before but probably well worth it.

I had a block paved driveway installed by a semi-cowboy outfit, the
soldier edging course holding it in place was pounded down onto a
concrete bed, after one winter it had broken free and turning the
steering wheel was making the driveway "walk" sideways.

The actual concrete bed was still intact, so I glued the soldier course
back in place with two beads of CT1 per block, and not one block has
moved or come loose in the ten years since then.

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On Fri, 3 Oct 2025 10:08:38 +0100, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 03/10/2025 10:05, Indy Jess John wrote:

On 02/10/2025 08:08, Jeff Layman wrote:

Concrete is not waterproof unless specifically treated.

I have never tried it myself, so I am just throwing the idea out here
for others to comment on:
Would mixing PVA into the cement make it waterproof permanently after
drying?

I have found it waterproof if enough cement is used to fill the gaps
between the sand. I am sure other things would work as well, possibly at
a cheaper price.

I've just bought a fresh 5kg bag of sand and cement mortar mix for
another job. I have no idea what the sand/cement ratio is because the manufacturer's (Tarmac brand from B&Q) data doesn't tell me. Is that
likely to be suitable for this job too?

Niok
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

Nick Odell wrote:

The "even works under water" claim never did Milliput any harm. Er...
has anybody actually seen any Milliput recently?

I think I have a couple of 'sticks' in my glues, etc container, it might
have gone off ...
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 04/10/2025 17:38, Nick Odell wrote:

On Fri, 3 Oct 2025 10:08:38 +0100, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 03/10/2025 10:05, Indy Jess John wrote:

On 02/10/2025 08:08, Jeff Layman wrote:

Concrete is not waterproof unless specifically treated.

I have never tried it myself, so I am just throwing the idea out here
for others to comment on:
Would mixing PVA into the cement make it waterproof permanently after
drying?

I have found it waterproof if enough cement is used to fill the gaps
between the sand. I am sure other things would work as well, possibly at
a cheaper price.

I've just bought a fresh 5kg bag of sand and cement mortar mix for
another job. I have no idea what the sand/cement ratio is because the manufacturer's (Tarmac brand from B&Q) data doesn't tell me. Is that
likely to be suitable for this job too?

If a bricklaying mortar mix it will be relatively weak. At least 4 parts
sand to 1 part cement but possibly 5 to 6 parts sand.
--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On Sat, 4 Oct 2025 17:49:03 +0100, alan_m <junk@admac.myzen.co.uk>
wrote:

On 04/10/2025 17:38, Nick Odell wrote:

On Fri, 3 Oct 2025 10:08:38 +0100, The Natural Philosopher
<tnp@invalid.invalid> wrote:

On 03/10/2025 10:05, Indy Jess John wrote:

On 02/10/2025 08:08, Jeff Layman wrote:

Concrete is not waterproof unless specifically treated.

I have never tried it myself, so I am just throwing the idea out here
for others to comment on:
Would mixing PVA into the cement make it waterproof permanently after
drying?

I have found it waterproof if enough cement is used to fill the gaps
between the sand. I am sure other things would work as well, possibly at >>> a cheaper price.

I've just bought a fresh 5kg bag of sand and cement mortar mix for
another job. I have no idea what the sand/cement ratio is because the
manufacturer's (Tarmac brand from B&Q) data doesn't tell me. Is that
likely to be suitable for this job too?

If a bricklaying mortar mix it will be relatively weak. At least 4 parts >sand to 1 part cement but possibly 5 to 6 parts sand.

Thanks,

Nick
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: uk.d-i-y

On 04/10/2025 17:38, Nick Odell wrote:

On Fri, 3 Oct 2025 10:08:38 +0100, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 03/10/2025 10:05, Indy Jess John wrote:

On 02/10/2025 08:08, Jeff Layman wrote:

Concrete is not waterproof unless specifically treated.

I have never tried it myself, so I am just throwing the idea out here
for others to comment on:
Would mixing PVA into the cement make it waterproof permanently after
drying?

I have found it waterproof if enough cement is used to fill the gaps
between the sand. I am sure other things would work as well, possibly at
a cheaper price.

I've just bought a fresh 5kg bag of sand and cement mortar mix for
another job. I have no idea what the sand/cement ratio is because the manufacturer's (Tarmac brand from B&Q) data doesn't tell me. Is that
likely to be suitable for this job too?

Niok

No. It will be a much weaker mix
--
"Nature does not give up the winter because people dislike the cold."

rCo Confucius

--- Synchronet 3.21a-Linux NewsLink 1.2