I am about to go and dig up my SLC - rebag it and return it to Weber!

[Andy Allen]

i use webber all the time .........and imo its spot on, good price, 25kg bag, 30mm depth.

when you mix it use your own judgement, its needs to be like cream, and not like pee.

 

[cornish_crofter]

i use webber all the time .........and imo its spot on, good price, 25kg bag, 30mm depth.

when you mix it use your own judgement, its needs to be like cream, and not like pee.

Did you batten the floor up and pour and level small areas one at a time? That is probably what I would do if I had my time again.

I have no idea how you're supposed to lay a 10mm screed without battening it when you mix it according to their instructions. It basically poured like single/double cream but then spread out very rapidly, I wouldn't say it was completely like water but it spread quite thin and I found it impossible to get the 10mm. It just ran away too much. Even pusing it back was useless as it just ran forward again.

I think the only way to achieve 10mm build up without battening would be to remove a litre or so of water when mixing it. I suppose it's easy to judge it when you've worked with it loads of times.

I then poured the next mix straight on top, and that has not helped by creating high spots. Having taken a proper look today I found that the difference in levels is actually up to 6mm in 6 feet. Ironically I would have been better off tiling on the concrete slab as that also varies by 6mm or so, and I would have saved myself a small fortune.

Oddly enough, putting 5L of water did make a difference. For the last couple of bags I went back to putting 5.25L as requested in the instructions. That was because I was dealing with a high point in the floor and I felt it would enable it to flow a bit easier over this area - I was needing to lay it about 5 mm or so. I found that the mix was not as watery as the fist bag, despite putting the same amount of water in - Bizarr.

Essentially I suspect that as you say, it may be possible to use less water and have a stiffer mix, just like mortar etc. However this wasn't effectively communicated to me by Weber. And as it may as well be the first time I've ever used this stuff I simply trusted that the information I was getting was accurate, in terms of coverage, consistency and the amount of water to be added.

 

[Andy Allen]

are you trying to make the floor level or flat?

if your floor isn't level then slc will simply run to the lowest point, the more slc you put down, the more it will fill the lowest points and make the floor level, but this will depend on the size of the floor and how much out of level it is

 

[cornish_crofter]

are you trying to make the floor level or flat?

if your floor isn't level then slc will simply run to the lowest point, the more slc you put down, the more it will fill the lowest points and make the floor level, but this will depend on the size of the floor and how much out of level it is

I am trying to make the floor level. I want to make the tiling as easy as possible and I want them to be flat.

The floor is around 3.5m x 2.6m.

The slab was about 5 to 6mm out of level between the high and low spots. I know this because I set about 30 odd screws in the floor and levelled them all up. You can tell how the levels change.

I am thinking of priming what is there then applying more SLC starting in the corner to give me a minimum 3mm of thickness at the highest spot and thus giving me about 13mm where there is currently no SLC. I guess I would just have to use a flooring trowel or similar to move it around gently to help it find its own level.

That sounds very easy but I have an odd feeling I'm going to screw it up again.

 

[dilz000]

Have u not got one of those spiked rollers that you roll through it to get any air bubbles out and level it out? There on tiletrader!!

 

[chrisroe]

you need a screed rake and a spikey roller

 

[TrumpersUnited]

I use a spatula like photo attached.

i always base coverage on 3m2 a bag at 5mm or 5m2 at 3mm.

I must admit i use weber floor flex loads and can't fault the stuff.

If you spend time preparing the floor and use a spike roller or spatula you'll never have a problem.

Hope you get it sorted out ok.

 

[cornish_crofter]

All these people telling me they've got no issue with the product makes me think I'm just being kak handed at the moment, which isn't helping a huge amount. Please be aware that I have no issue with the product itself - it's the misinformation that is a problem.

I still can't reconcile how you would manage to build up 10mm when mixed according to the instructions though.

I am coming to the conclusion that the product is OK, it just won't do what they said it would when you mix it according to the instructions. As I've said before, I've hardly ever used this stuff before. The last time was 4 years ago half heartidly. Using it for the first time you have to put your faith in other people. when the manufacturers tell you to mix it with 5.25L of water per bag and then tells you you can lay 10mm in one go you tend to believe them, unless you've worked with it and know that not to be the case.

I see you've used packers stuck together to give you your height. I did a similar thing with screws into the concrete. The idea was to keep the screws just visible.

I like your idea of a spatula on a pole - I think I'll adopt the same. It gives you good reach. I think I may see if I can get a spiked roller as well and a cheap garden rake.

I think if I had my time again I would have done it in 2 hits or battened it out and done it in sections. It's too late for the battens now. I just want to get it level and flat. To that end I think I'll add the max amount of water I can to make the slc flow better.

The coverage of 3m squared at 5mm would equate to 1.5m squared at 10mm. Being that I worked out the averaga height at 10mm 7 bags should have definitely done it. I can't think why it didn't. Although I think I may have gone 3mm over in one corner thanks to trying to build it up and over doing it, but that shouldn't have made that much of a difference.

 

[White Room]

The spatula is similar to what I use but mine has a 600mm blade

 

[Aston]

did you check the floor prior to laying the slc??

did you put a straight edge down to see where there was high spotswhere?

or do you just pour and hope for the best......lets know how you went about establishing things

 

[newlineuk]

Do weber have quartz sand aggregate to mix with their slc?

 

[White Room]

I've used course sharp sand or grano dust to bulk the slc

 

[TrumpersUnited]

not as far as i'm aware. it's a fibre reinforced leveller can go up to 50mm in one hit.

 

[newlineuk]

not as far as i'm aware. it's a fibre reinforced leveller can go up to 50mm in one hit.

That's the answer I was looking for.
But to get to 50mm thick you would need to batten out and that I think is where cornish_crofter has come unstuck.
It says on the bag what thickness it will go to but dosn't say how, to get to it.

 

[cornish_crofter]

did you check the floor prior to laying the slc??

did you put a straight edge down to see where there was high spotswhere?

or do you just pour and hope for the best......lets know how you went about establishing things

OK this is what I did.

1) Swept floor.

2) Put a level going from the centre of the room out to corners and sides to give me an idea as to where the high spots were.

3) Set a screw in the centre. Judging by where how the level behaved I set this at app 10mm. I knew it would be less in some areas and more in others

4) Drilled, plugged and set screws around the floor app 2 feet apart in a rough grid pattern. Each screw was adjusted to be level with the centre screw or datum screw. I also checked the screws with each other to make sure the heights were consistent. By the time I'd finished I had about 30 odd screws all at the same height as one another. If I couldn't reach a screw with the 6ft level I would take the height of other screws and cross check them. A HELL of a lot of time went into this.

5) Cleaned the floor again, only this time more thoroughly.

6) I then checked again for level screws. As for high spots on the floor, the height of the screws illustrated the high points. So I could see where more SLC would be needed. Also I could see where high spots were and knew that when I poured slc there it would go further so I had to be ready.

7) Primed about 1/2 the floor. I did this so that the SLC would land on it whilst it was still tacky, but not too wet.

8) Mixed the first bag of SLC according to the instructions. As I was working alone I couldn't pour and mix at the same time, so I added about a quarter of the bag at a time. I added 5.25L measured out of clean water. It was at this point I noticed that it was quite runny.

9) equipped with a 6ft derby, plasterers trowel and levels I poured the first mix. Thinking I could settle it at 10mm depth using the screws to guage the depth and the derby to level it I poured it across the far end of the room. It was at this point I found out that this wasn't the case.

10) Phoned Weber and spoke to their product manager and explained that keeping it to 10mm thick was not possible as it was too runny. He advised me to use less water, maybe 4.75l or 5l in the next mix.

11) I then mixed up the 2nd with less water, about 4.75L. I had taken some of the water out of the bucket before mixing. In an effort to get the depth I then poured it on top of the first mix. I suspect this was a mistake. Although I did make an effort to level it out I must have paid too little attention to a corner.

12). As I worked along I mixed up and poured the floor in strips across the width of the room. I varied the water between 5 and 5.25L in an effort to get a feel for the mix. Again I used the derby and the plasterers trowel to level and move it along. I did try to use the derby in the other direction (end away from me as opposed to holing it parallel to the edge of the mix. Where it was slumping too much towards the front I was pushing it back to cover the screws and draw it forwards again. I suspect this created a slight ridge in one area, but I managed to scrape most of it away after a few hours.

13) As I got perpendicular to the door I started working with my back to the door and carried on the same vein. At this area the concrete slab rises a little so I started to mix 5.25L mixes and work back.

14) I only managed to get a couple of mixes in this direction when I ran out. I was hoping that I would be able to work my way out of the door adding the right amount of SLC to sit inside the floor, levelling out as I go, and it would be stopped by the door threashold and walls etc and settle in place.

I didn't spend a huge amount of time trying to get it dead level but I didn't pour and hope for the best either.

Maybe the problem lies in that method.

 

[cornish_crofter]

That's the answer I was looking for.
But to get to 50mm thick you would need to batten out and that I think is where cornish_crofter has come unstuck.
It says on the bag what thickness it will go to but dosn't say how, to get to it.

That is what I understand, and I think you are spot on, as I have said earlier and mentioned to both the tile shop manager and the Weber guy I spoke to today.

 

[cornish_crofter]

I forgot to say I did prime the rest of the floor when I had reached it. Again the SLC went down wilst tacky.

 

[The Legend; Phil Hobson RIP]

I have put this method on before, similar to the screw idea. But by using runners set by laser, I find I can get this floor 56m2 accurate to 1mm you could play pool on it

 

[newlineuk]

Having used screed for last 25years it's easy for me to say that you could have done it a better way, but what's done is done so, your best option IMO would be to prime and then use a weber product to patch up the low points in patches then skim over the whole floor.
When you've done m2 upon m2 you get the feel of the floor, feeling the low points come natural even with the smallest of trowels.
If I lived closer I would have come over and helped you out. Perhaps one the guys on the forum that do's live locally could help?

 

[The Legend; Phil Hobson RIP]

Finished job, 1m x 500mm porcelain, has to be flat for these tiles

 

[andy8758]

Dear Cornish_Crofter - Nothing is as bad as you sound on this thread. Mistakes and frustration are called "experience."

Experience tells you now that the manufacturers "recommended mixing ratios" are not accurate. Mixing SLC is a bit like mixing adhesive - when you have done it a few times you will get a feel for how "runny" or "thick" you want it to be. Thicker makes it easier to spread accurately, runnier makes it more efficient self levelling. In any event, as a professional, carry spares before you start the job - as someone else suggested if you do not need the extra bags, then you can use them for another job - they have a good 12 month shelf life. I have never found slc that covers the recommended coverage area, but the manufacturers develop their information under laboratory conditions - you are "on site" and that just aint gonna work - again experience is learning how much coverage you get per bag - not what the manufacturer says you will get - how often do you get the recommended coverage from a bag of tile addy?

The SLC you used is very capable of levelling to 10mm in one go. But if it does not go quite right, do a second coat as someone else suggests. If it all goes horribly wrong, remove the hardened slc and start again. Sure you lost some time. Chalk it up to experience.

A tiler I was chatting to last month, same age as me, been in the trade since he left school 30 years ago and has his own tiling company now with 20 employees. He told me that when he started out, laying a screed was a skill all tilers were expected to have. Nowadays too many "trainees" never learn the ancilliary skills that can make your life as a tiler so much easier. All tilers would benefit from plastering skills, screeding skills, and rendering skills - and laying a slc is a part of that. You are having to learn the hard way - losing time and money -whereas the apprentice can make their mistakes at their employers expense - and then only once!

So my honest advice to you is to take several deep breaths, accept the experience you have achieved from this, then get stuck in, and finish the job to a high standard. The next time will be so much easier. Then remember that when those crinkly old sages on here tell us we are going to struggle learning all the skills of a tiler because we have not done an apprenticeship - accept their advice and plan for jobs over running, and paying for our own mistakes.

All the best, and get stuck in again tomorrow.

Andy

 

[cornish_crofter]

Finished job, 1m x 500mm porcelain, has to be flat for these tiles

That looks nice there Phil

I think that is what was meant when the Weber guy said it could be done. Unfortunately I spoke to someone else who went and consulted his colleague. If his collegue was thinking about how to get the 10mm in one go that part of the message didn't get to me, although the chap I spoke to reckons he did ask the question about battening it out and the reply is that I didn't have to.

The way I see it I've got 2 options now.

1) Dig around the screws and unscrew them a few turns each to bring them out 3mm above the high point and basically repeat the exercise

2) dig out some channels and put some battons in, levelling out as necessary and do what Phil did. I reckon a bolster chisel or a cutter would do the job..

The 2nd idea is a favourite of mine at the moment. It's more automated and it's the same method I use for rendering walls and screeding floors.

Phil, how do you use a laser to level the battens?. I have a rotating laser level but it won't put a line that far down.

Also, NewlineUK, would you or anyone else care to comment on where I may have gone wrong with the way I did it before please.

Andy, just read your post above. I think I will redo it but I'm not going to take it up. I have spare height on the floor so I'm going to bring it up about 3mm above the highest point and level it to that. I've decided to wait until I have all the material. CTD have given me 2 bags, all their stock at the moment. The Weber rep has basically said he will talk to the product manager about more materials being free issued to me.

What you say about mixing ratios to stiffness makes perfect sense, but again I've said this a number of times, I trusted the manufacturer to give me sound technical advice on this. That is probably my biggest mistake in this instance. Had we had this conversation before I would have bought extra bags and probably battened it out as Phil did his, rather than stiffen up the mix.

 

[The Legend; Phil Hobson RIP]

Hi Andy, I suppose that I am one of the crinkly old sages, am I?:yikes::lol:

 

[newlineuk]

Finished job, 1m x 500mm porcelain, has to be flat for these tiles

Nice...
Did you run off from that pillar?

 

[Gazzer]

That looks nice there Phil

I think that is what was meant when the Weber guy said it could be done. Unfortunately I spoke to someone else who went and consulted his colleague. If his collegue was thinking about how to get the 10mm in one go that part of the message didn't get to me, although the chap I spoke to reckons he did ask the question about battening it out and the reply is that I didn't have to.

The way I see it I've got 2 options now.

1) Dig around the screws and unscrew them a few turns each to bring them out 3mm above the high point and basically repeat the exercise

2) dig out some channels and put some battons in, levelling out as necessary and do what Phil did. I reckon a bolster chisel or a cutter would do the job..

The 2nd idea is a favourite of mine at the moment. It's more automated and it's the same method I use for rendering walls and screeding floors.

Phil, how do you use a laser to level the battens?. I have a rotating laser level but it won't put a line that far down.

Also, NewlineUK, would you or anyone else care to comment on where I may have gone wrong with the way I did it before please.

use a staff !

 

[doug boardley]

weber actually do a slc that'll do 50mm in one hit, was gonna use it today (but not to that depth) but due to unseen builders errors that I've had to sort out, will be using it tomorrow instead

 

[cornish_crofter]

use a staff !

Sorry Neale - I'm being thick again, I've had information overload lately - could you please explain where you're coming from? Are you suggesting I measure down from a laser line to the batten and keep that measurement constent at all points?

 

[newlineuk]

That looks nice there Phil

I think that is what was meant when the Weber guy said it could be done. Unfortunately I spoke to someone else who went and consulted his colleague. If his collegue was thinking about how to get the 10mm in one go that part of the message didn't get to me, although the chap I spoke to reckons he did ask the question about battening it out and the reply is that I didn't have to.

The way I see it I've got 2 options now.

1) Dig around the screws and unscrew them a few turns each to bring them out 3mm above the high point and basically repeat the exercise

2) dig out some channels and put some battons in, levelling out as necessary and do what Phil did. I reckon a bolster chisel or a cutter would do the job..

The 2nd idea is a favourite of mine at the moment. It's more automated and it's the same method I use for rendering walls and screeding floors.

Phil, how do you use a laser to level the battens?. I have a rotating laser level but it won't put a line that far down.

Also, NewlineUK, would you or anyone else care to comment on where I may have gone wrong with the way I did it before please.

Andy, just read your post above. I think I will redo it but I'm not going to take it up. I have spare height on the floor so I'm going to bring it up about 3mm above the highest point and level it to that. I've decided to wait until I have all the material. CTD have given me 2 bags, all their stock at the moment. The Weber rep has basically said he will talk to the product manager about more materials being free issued to me.

What you say about mixing ratios to stiffness makes perfect sense, but again I've said this a number of times, I trusted the manufacturer to give me sound technical advice on this. That is probably my biggest mistake in this instance. Had we had this conversation before I would have bought extra bags and probably battened it out as Phil did his, rather than stiffen up the mix.

Difficult to say without being onsite at the time, but the size of the floor area and at that depth without battens to stop spread and not having a great deal of experiance with slc I would have had someone mixing up and two buckets on the go.
Anyone else care to advise?

 

[DHTiling]

weber actually do a slc that'll do 50mm in one hit, was gonna use it today (but not to that depth) but due to unseen builders errors that I've had to sort out, will be using it tomorrow instead

So do Stonefix,..

 

[The Legend; Phil Hobson RIP]

Hugo, as above, use a staff. Find your highest point set your laser height to whatever mark a staff ( just like using a dumpy level) set dots to this level all around the floor (grid of levels) I don't use batons, the runners in my pics are polymer sand and cement, left to set. I always put some rapid set adhesive in the mix, to send it off fast.

Using this method you can go from 0 to 30mm, Fill in the bays, (I work to 2m bays) with slc. Then when floor is poured and cured, you can remove runners and replace with slc. Or if you feel confident the are solid leave them in. The same way I was taught To render/ screed, by screed I mean sand and cement screed, not slc

 

[andy8758]

That looks nice there Phil

What you say about mixing ratios to stiffness makes perfect sense, but again I've said this a number of times, I trusted the manufacturer to give me sound technical advice on this. That is probably my biggest mistake in this instance. Had we had this conversation before I would have bought extra bags and probably battened it out as Phil did his, rather than stiffen up the mix.

I have tried following these "manufacturers recommendations" - now I make my own mind up (lol). It reminds me of my wife cooking - she never uses scales to weigh, or a measuring spoon to measure - she pours and when the consistency is right, she bakes. And it tastes good after!