DIY Doctor UK DIY Forums

Hi,

Has anyone used this produce from Lafarge?

-Slablayer-

It says it is:

- Ready to use just add water. No mixing required
- Consists of cement, sand and specially selected aggregates
- Designed for laying patio paving slabs

This sounds awesome to me but how do I work out how many kgs I need?

If I use the calculation tool it says nearly 1700kgs, but that seems an awful lot...

Ideas are appreciated.

:)

I used a couple of bags of Lafarge Slablayer a week ago, with questionable success.

I was laying a dozen small (300 X 300) slabs, and followed the instructions [level out 25mm deep, sprinkle with water using a rose on a watering can, put the slabs on top.]

The mortar appears to have set as a flat bed, BUT has not adhered to the underside of the (new) slabs - there is some movement.

The instructions say nothing about how long to leave the mortar to set, about whether to wet the slabs first, and whether it is better to under-water the mortar ("sprinkle with water using a fine rose until the Slablayer is wet through" is unhelpful as one cannot see when the water has gone through the mix.)

Constructive comments welcome - on how to fix the slabs to the mortar bed, and/or how better to use the Slablayer.

To the OP who asked how much to use; each 20kg bag covers 0.6 m2

[I know that professionals who lay miles of slabs a week wouldn't use Slablayer, but please remember those of us who only want to do one small job.

Update: I emailed to Lafarge
" .. although the mortar has set firmly as a mortar layer underneath the slabs, it has not adhered to the slabs - there is a sandy layer on top of the mortar. Suggestions, please, for re-laying the slabs so that they stick to the mortar layer?
"
and had the following reply:
"From what you state, it seems likely that the slab has sucked the moisture from the Slablayer, thus preventing the cement hydration and bond strength gain. To prevent this, either damp the slabs down a little prior to placement or wet the slabs thorughly a few hours after placement. An external PVA would solve this problem and guarantee a good bond, especially if there is little mechanical key on the underside of the slab."

I followed both suggestions; watering the slabs AND coating them with exterior PVA (not woodworking glue) before laying them - and it worked.

MickBee wrote:Update: I emailed to Lafarge
" .. although the mortar has set firmly as a mortar layer underneath the slabs, it has not adhered to the slabs - there is a sandy layer on top of the mortar. Suggestions, please, for re-laying the slabs so that they stick to the mortar layer?
"
and had the following reply:
"From what you state, it seems likely that the slab has sucked the moisture from the Slablayer, thus preventing the cement hydration and bond strength gain. To prevent this, either damp the slabs down a little prior to placement or wet the slabs thorughly a few hours after placement. An external PVA would solve this problem and guarantee a good bond, especially if there is little mechanical key on the underside of the slab."

I followed both suggestions; watering the slabs AND coating them with exterior PVA (not woodworking glue) before laying them - and it worked.

.

Hi,

How did you manage to dig the stuff up that had set hard ?..my husband has had exactly the smae problem, but had laid the whole patio, only to find they have not stuck. needless to say he is v upset !...

I've just used it for my driveway.

I used a scalp subbase - 50mm wacked down -10+ passes.

Then 50mm of slablayer wetted with the 'mist' thing on hosepipe.

The slabs were soaking as it had been raining. The slabs were 600x900 50mm thick!!
Ridiculously heavy!!

Seems to have worked very well, its solid as a rock.

Id recommend slablayer but would definitely wet both the slabs and the mix more than just a sprinkle.

Glad it's worked for you (jmarsh), too. I also successfully re-layed a path of 600 X 900 X 50mm slabs (50 kg each) using a 25mm layer of Slablayer - wetting the slabs after a priming coat, and wetting the Slablayer well.

Apologies to sheena for not replying - I never got an email alert. For me, the hard layer to be removed was only 300 X 300 X 25 thick, so no problem. Hope your husband succeeded in removing the patio slab.

Slab layer is a cement based material containing specially selected sand and cement for use under patio paving slabs. It is easy to use and requires no mixing and gradually over a period of time develops hardness to support the slabs.

There's more information at http://www.DIYcement.com

Hi guys, fairly old post but still a very popular one. As you can see from YouTube we have used a lot of Lafarge products and found most of them brilliant but it has to be said we found the slab layer of no more use than normal sand and cement and consuderably more expensive. The best products are the pointing mortar and the postcrete, both of which can be seen at the links below but for laying a patio, go here for help https://www.diydoctor.org.uk/projects/patio.htm

For poiting a wall go here https://www.diydoctor.org.uk/projects/Po ... ckwork.htm

For concreting fence posts go here https://www.diydoctor.org.uk/projects/co ... tcrete.htm

So what sand do you use putting slab down? Fine Builders sand?

Doesn’t mention needing a sub base/mot type 1?