To prime or not to prime

[kaharrison9]

Hi all
Hoping for some advice.
Pricing up for a bathroom and will be taking off the tiles.The surface is plasterboard and plaster.The customer has decided he doesn't want tanking and the tiles are 250mmx330mm.I was planning to use Bal spf but have to prime the walls with Bal apd twice and neat which i've worked out as needing 4 tins and paying around £13.50 per tin proves expensive.
If i use the Bal white star tubbed adhesive will i still need to prime the surface before?also will a 5-6mm thin bed solid bed trowel be fine for this size tile?
Thanks for any help
Kev

[grumpygrouter]

Hi all
Hoping for some advice.
Pricing up for a bathroom and will be taking off the tiles.The surface is plasterboard and plaster.The customer has decided he doesn't want tanking and the tiles are 250mmx330mm.I was planning to use Bal spf but have to prime the walls with Bal apd twice and neat which i've worked out as needing 4 tins and paying around £13.50 per tin proves expensive.
If i use the Bal white star tubbed adhesive will i still need to prime the surface before?also will a 5-6mm thin bed solid bed trowel be fine for this size tile?
Thanks for any help
Kev

Four "tins" of APD to prime... how big is the area?

[kaharrison9]

It's 23m2 and i may have got my calculation wrong could be between 2-3 tins.

[grumpygrouter]

It's 23m2 and i may have got my calculation wrong could be between 2-3 tins.

a 2.5ltr tub should do way more than 23m2. You buying small bottles or something?

[kaharrison9]

Hi Grumpy
I looked at the Bal production selection book and it says 2.5L undiluted does 12.5L-25L.With there been a large varience in coverage i'm working out an average of 18-19L per 2.5L.
I early spoke to the Bal technician and he said it would need priming undiluted twice if this been the case and the bathroom been 23m2 does it mean i have to work out the amount needed is for 46m2?
I cannot work on experience but does a second prime not use as much as the first or do i need to prime where there has been previous tiles?
Hope i'm making some sense.
Cheers
Kev.

[Gazzatile]

I use Bis Flexibond get aroud 50mt tub when priming

[grumpygrouter]

Hi Grumpy
I looked at the Bal production selection book and it says 2.5L undiluted does 12.5L-25L.With there been a large varience in coverage i'm working out an average of 18-19L per 2.5L.
I early spoke to the Bal technician and he said it would need priming undiluted twice if this been the case and the bathroom been 23m2 does it mean i have to work out the amount needed is for 46m2?
I cannot work on experience but does a second prime not use as much as the first or do i need to prime where there has been previous tiles?
Hope i'm making some sense.
Cheers
Kev.

The second coat uses much much less than the first coat. The first coat pretty much seals most of the substrate, you apply the second, in a perpendicular direction to make sure you have not missed anywhere. A lambswool painting roller is very economical. You will waste much more with a paint brush.

[kaharrison9]

Cheers for that advice Grumpy
Could i also ask if i do use Bal white star do i need to prime and do you think a 5-6mm thin bed solid bed trowel would be fine with 330mmx250mm trowel?
Thanks very much
Kev

[grumpygrouter]

You do not need to prime with BAL White Star and try using a 6mm trowel first and check coverage. if it isn't sufficient, go up to an 8mm and see how that is. Any bigger and you are in danger of having too thick a bed for dispersion adhesive.

[Fekin]

250 x 330 tiles, then personally I'd go cement based adhesive.

[oldgit]

bal data will tell you to prime new plaster with apd neat or sbr 4to1,with all there tubbed addy.
i checked this tonight,but if you were to use mapei d2 you need not prime at all.

[grumpygrouter]

bal data will tell you to prime new plaster with apd neat or sbr 4to1,with all there tubbed addy.
i checked this tonight,but if you were to use mapei d2 you need not prime at all.

Where did you find this info Oldgit, it says nothing about it in the BAL Fixers Guide?

[oldgit]

Where did you find this info Oldgit, it says nothing about it in the BAL Fixers Guide?

http://194.223.92.131/pdf/Technical%...White_Star.pdf


(1) Do not use shower for at least 2 weeks following completion of grouting - BS
5385: Part 4: 1992, clauses 6.3(f) and 6.4(h).
(2) Provided surface is sufficiently flat
(3) Check suitability of sheets/boards for the intended purpose with the
manufacturer.
(4) In frequently wet conditions tank out with the BAL-WP1 TANKING SYSTEM.
(5) The drying time will be extended in colder temperatures, when fixing to
impervious backgrounds or when fixing tiles of low porosity.
(6) Cured adhesive.
SURFACE CONSIDERATIONS
NEW CONCRETE/BRICK/BLOCK WALLING: Before
rendering/plastering/tiling allow walls to dry out by exposure to air for at
least 6 weeks. Direct fixing to brickwork or concrete may be carried out,
providing the surface is sufficiently flat. However, direct fixing to
blockwork is not recommended.
NEW CEMENT/SAND RENDERING: Before commencing tiling, allow
new rendering to dry out by exposure to air for at least 2 weeks or for
rendering based on BAL-QUICKSET CEMENT, 24 hours.
PLYWOOD/CHlPBOARD/FIBRE-RElNFORCED CEMENT SHEETS:
Sheets/boards must be dry, securely fixed and rigid, e.g. screwed to a
seasoned timber framework at 300mm centres vertically and horizontally.
Moisture resistant or exterior grade boards should be used. Seal the
reverse side and edges with BAL-BOND SBR to prevent distortion from
atmospheric changes. Do not seal or prime surfaces to be tiled. Check
suitability of sheets/boards for the intended application with the
manufacturer.
GYPSUM PLASTERBOARD BACKGROUNDS: Ensure that boards are
dry, securely fixed and rigid with no protruding fixings and the face
intended to receive the decorative finish is exposed.
NEW GYPSUM PLASTER: Before commencing tiling, ensure that the
plaster has been allowed to dry out by exposure to air for at least 4
weeks. Ensure that the finish coat has been applied and that the plaster
is free from dust, efflorescence and friable material. Cut back any
defective areas, including badly cracked plaster, to straight horizontal and
vertical edges. Thoroughly dry brush background and edges and make
good with plaster or a suitable non-shrinking filler. Plaster having a shiny,
polished surface should be thoroughly brushed with a stiff bristled brush,
followed by priming with a 1:4 BAL-BOND SBR:water mix or a 1:1 BALPRIME
APD:water mix. Allow the primer to dry.
FIBRE MESH REINFORCED CEMENT FACED TILE BACKER
BOARDS: Ensure that boards are dry, securely fixed and rigid and that
any fixings do not protrude. Do not seal or prime surfaces to be tiled.
GLAZED TILES/ BRICKS: Ensure that existing tiles/bricks are firmly


i wondered early on if id been priming for years without need,so i had a quick read.

[david campbell]

white star was my favourite tubbed addy until reading that,don't use shower for 2 weeks,we aint tiling for hobo's are wee!

[Dave]

Thats just shiny though...if you are following directions to the T..

Plaster having a shiny,
polished surface should be thoroughly brushed with a stiff bristled brush,
followed by priming with a 1:4 BAL-BOND SBR:water mix or a 1:1 BALPRIME
APD:water mix. Allow the primer to dry.

[oldgit]

Thats just shiny though...if you are following directions to the T..

i read it like that as well but does it mean prime plaster anyway or only if its shiny it can be read both ways doesnt make it totally clear.
even years ago we always used pva at 10:1 on all plaster,just how i was taught,i just changed over to acrylic primer when the trade deemed that was the way to go.
granfix still say use there pva primer

[grumpygrouter]

With "shiny" i take that to mean "polished" plaster which is difficult to tile onto as the adhesive can't get a grip. i was taught that you need to rough it up and then prime. I was also taught that "normal" plaster is ok for adhesion. "polished" plaster I believe won't even take a paint finish, but I am sure the plasterers on here will correct me if I am wrong. Whitebeam?

[whitebeam]

Your spot on there grumpy

[oldgit]

Your spot on there grumpy

what is the purpose of polished plaster?

[Dave]

what is the purpose of polished plaster?

Just an over keen plasterer..

[grumpygrouter]

what is the purpose of polished plaster?

i believe it can be classed as a finished product and can be done in various shades and colours.

[david campbell]

what is the purpose of polished plaster?

a finish that can be painted over once undercoated!

[kaharrison9]

Thanks all for your input,especially Oldgit and Grumpy.
I'm wanting to do everything correct and use quality products but am finding it hard to justify the cost of using Bal products to some customers.
I am going to start looking at Mapei products which are slightly cheaper and are well reccomended.Trying to get a balance with my quotes.
Cheers
Kev

[lucius]

Polished plaster as in highly polishing say a multi finish is only done if you have something against the painter, it used to be the spec in hospitals years ago but i dont think any more Polished Plaster is a specialised technique involving colours.
Lucius

[Sir Ramic]

Is it any wonder that there is such confusion when there are such documents about.
All we need to know is Yes or NO.
This is why i have said i never prime with tubbed adhesives ( unless plainly stated on the bucket) .

[grumpygrouter]

Just another case of having to read stuff very carefully IMO. Same as the Priming/Sealing issue with ply. Lots of peeps on here think it is the same thing and get themselves confused.

[surfacetiling]

Hi Folks,

Always interesting to hear how everyone approaches their jobs, especially when it comes to substrate prep. I have always used the same method no matter what surface I am tiling onto, any PVA product unibond etc.. then i add some fine sand when the pva is half set. On a really dusty surface I will Pva a second coat. My apprentice is a dab hand at this. PVA 1 part water 3 part. I find its the cheapest way to prime any surface and has never let me down. I never use bal unless the client buys it with the tiles. Some shops will push the adhesive on the sale because the margin is huge. I have an account with Mapei for the last four years never let me down great open time and really easy to trowel on. It might be useful if you have the storage space to bulk buy from Mapei the discount is huge. I use keraflex maxi most of the time. I dont change adhesive to suit the tiles I dont see the point.
Some times an architect or QS will give recommendations for the materials to be used but they are always just copied from a suppliers website.

I suppose my point is tilers have been using the same methods and materials for years forget the technical specs on the bags of adhesive and use the tried and trusted method.

[doug boardley]

Hi Folks,

Always interesting to hear how everyone approaches their jobs, especially when it comes to substrate prep. I have always used the same method no matter what surface I am tiling onto, any PVA product unibond etc.. then i add some fine sand when the pva is half set. On a really dusty surface I will Pva a second coat. My apprentice is a dab hand at this. PVA 1 part water 3 part. I find its the cheapest way to prime any surface and has never let me down. I never use bal unless the client buys it with the tiles. Some shops will push the adhesive on the sale because the margin is huge. I have an account with Mapei for the last four years never let me down great open time and really easy to trowel on. It might be useful if you have the storage space to bulk buy from Mapei the discount is huge. I use keraflex maxi most of the time. I dont change adhesive to suit the tiles I dont see the point.
Some times an architect or QS will give recommendations for the materials to be used but they are always just copied from a suppliers website.

I suppose my point is tilers have been using the same methods and materials for years forget the technical specs on the bags of adhesive and use the tried and trusted method.

PVA is a deffo no no in a tilers arsenal

[surfacetiling]

Hi Doug why do you say that? Ive been using it for years!!! interested to hear your opinion

[grumpygrouter]

Hi Doug why do you say that? Ive been using it for years!!! interested to hear your opinion

Much said on these forums about why not to use PVA in tiling, I will find you a link to read if someone doesn't beat me to it.