diy related: Laying granite on concrete

[zygo]

Wow. If I could leave thanks more than once I would, penno. It's a long shot but I'm in Essex. So where are you? Aberdeen, I expect!
z

 

[penno]

Ouch long drive im afraid mate, im in Manchester

 

[zygo]

No matter. Nice idea though! Thanks.
(Now half of Lancashire will be PM-ing you to ask if they can borrow it!)
Z

 

[zygo]

Thanks for the advice, guys. Here's my plan of attack - please be brutally honest!

ROOM: 3.4M by 2.4M. (about 8 square metres). No skirting. New sub-floor of 80mm deep sand/cement laid 3 months ago (I don’t do ‘quick’). Not exactly square.:huh2:

ME: Fussy, decent DIY skills but never laid floor tiles. I’m working alone

TILES: Polished granite 305x305x10 (Absolute black), 2mm bevel edge.
SCREED: SBR (Styrene Rubber Butadiene) if I can find it (PVA if I can’t).
ADHESIVE: Mapei Keraquick grey from Screwfix at £6.89/5kg (How many?):huh2:
GROUT: Mapei Ultracolour Plus in Black (or Anthracite?) at £10.99/5kgs (How many?):huh2:

1. Sweep and vacuum sub floor.
2. Apply a sealant, starting in the furthest corner from the door
3. Leave to dry – one hour. Breakfast.:8:
4. Pour self-levelling screed, spreading with a steel float.
5. Leave to go off – overnight. Allow some ventilation.
6. Find centre of each wall and pop a chalk line to divide the room into quarters (each 2 sm)
7. Mix enough adhesive to cover about two metres.
8. Apply to area 1 (further from door) and spread with 10mm notched trowel (£6.99 Screwfix).
9. Using standard white cross spacers, lay first 15 tiles, starting at centre where lines cross (if I can still see them under the adhesive!) – leaving gaps by the two walls.
10 Check with level for even laying
11 Measure and cut wall-edge tiles on wet saw, and lay checking against the rest with a level
Stop for tea.:8:
12 Repeat steps 7 to 11.
Stop for the day
13 Repeat steps 7 to 11.
Stop for tea
14 Repeat steps 7 to 11, cutting round doorway.
Leave 48 hours.
15 Grout the joints.
:hurray:

Thanks will be given for all input, as usual. I'd especially appreciate some guidance on quantities of adhesive and grout (If there is a 'standard' grout gap between 12 inch floor tiles, what is it? Otherwise, I'll use some I already have).
z

 

[zygo]

Oh, just one more thing.
Access to this converted garage is directly from the patio, which inevitably means stepping up into the room with wet shoes sometimes. Is there anything that can be applied to create some anti-slip properties? Someone's mentioned a product that they think is called 'Galaxy'. Anyone have experience of this? Where can you get it?
Z

 

[Tiler84]

Try and cut all tiles in as you go as its a horrible job spending all day doing just cuts. if you room is not square then make sure you even up the difference on each wall to make sure your line is straight. make sure you wipe down tiles as you go and excses out of the joints so it does not poke through the joints when grouting.

 

[zygo]

Thanks for that advice, Tiler84. Especially the bit about wiping out the joints before it sets hard.
z

 

[medlar]

i know this may sound silly mate,but you said start from the middle of the floor,before laying 1 tile,make sure you know wether to start on a full tile from centre line or half tile from centre line.
you could actually check to see if your floor is square,mark your centres out,from the exact centre measure 4 foot up the line,then from the exact centre measure 3 foot,now draw a line connecting both marks,(would look like a triangle from the centre,if the measurement between both points is 5foot,your floor is square

 

[zygo]

Aha. The old 345 trick to find a right angle (first discovered by Pythagoras, I think). It's easy for me to know the room isn't square because the width at one end is 20mm bigger than the other (and the length is around 10mil more if I recall. But you make a bloody good point, medlar, because I had not considered if any or the corners was 90 degrees. :mad2:
Top man, medlar

I believe I need a whole tile from the centre as the finished job will result in an even number of tiles in both directions (six - or parts thereof - on each side for the length, and four each side for the width). Good point though, and well worth mentioning in case some other amateur is secretly taking notes for his room!
Z.

 

[grumpygrouter]

Zygo, DO NOT USE PVA as a sealant. It has no place in tiling. If you need to seal your concrete and you can't get SBR of any sort - trade tiler do it - than you should obtain an acrylic primer of some sort. If you use Mapei adhesive they have their own preferred primer, check it out. If you use PVA you expensive tiles will be secured to nothing more than a thin layer of PVA, NOT your concrete floor. If moisture penetrates through to the pva layer for some reason, your tiles will come up!!

 

[zygo]

Thanks for the warning grumpygrouter. This could be the best bit of advice I have had. The concrete subfloor is about 80mm thick and lies on top of 80mm of Celcon, which has a dp membrane below it placed on top of the original garage concrete base. I don't know if that original base was laid on a dpc but it never showed signs of any dampness in 25 years. However, I will heed your advice because the extra protection I have since read about is well worth the few quid it wall cost to buy SBR. Would five litres be enough for 8/9 square metres?

z

 

[grumpygrouter]

Hi Zygo, glad to hear you have taken on board the advice re SBR. 5ltr will be plenty. It needs to be diluted 4parts water to 1 part SBR (this is BAL Bond SBR) and then brushed or rollered on. Allow to dry and then tile. you must commence tiling within 24 hrs.

You can get BAL stuff in 1 ltr packs wich will be plenty for your job I should think. if you have difficutly obtaining it where you are, Trade Tiler (our sponsors) sell 5 ltrs of an equivalent and can be delivered to you.

 

[zygo]

Sh**! That was close.

I was gonna apply the SBR to the subfloor BEFORE spreading the self-levelling screed. Should I be doing it the other way round then?:huh2:

z

 

[grumpygrouter]

No you were right the first time Zygo. Concrete or screed generally doesn't need priming (unless your adhesive manufacturer says so) but it can be a good idea to do so as it helps to "lock in" any residual dust. Have you ever swept a concrete floor? There always seems to be more sweeping required.........

Seal the floor with SBR and then level it. No need to prime the leveller (usually) you can tile straight on top of it.

 

[zygo]

Phew!
Just one more point on this topic, Grumps. You mentioned that I should lay tiles on the sealed subfloor "within 24 hrs". Does this mean that I should apply the SL screed within 24 hours of painting the subfloor with the SBR?:huh2:
Thanks for the advice on needing only 1 litre of SBR for 8sm of floor area diluted 4:1.

Z