Tegula blocks on concrete steps

[Mark9691]

Hi, Is it possible to face off the risers and treads of concrete steps with concrete blocks (Marshalls tegula). I read in a book that if you clean the concrete off and paste neat cement and water to the concrete surface before bedding the blocks down on a strong mix of say 3 to 1 they will hold OK. Trouble is they are small blocks and I'm worried they may become dislodged and someone may go arse over tit. Perhaps there are extenal concrete to concrete bonding products available? Any help thankfully received. Regards, Mark

[Mark9691]

Wot no replies??

Here's a picture so you can see what I want to do. Also forgot to mention, I would prefer no mortar btw the blocks to match existing.

Any Ideas??

[lutonlagerlout]

are those one cemented on mark?
looks tidy enough ,but i would guess you need some heavy duty exterior tile adhesive,look on the suppliers page
other than that you have the issue of the non-face part of the block showing on the treads
and what will keep the KD sand in place?
if its a DIY project i would say go for it,but i wouldnt want to risk my name doing it for someone on a pro basis(only because they are not designed for it)
cheers LLL

[Mark9691]

LLL, many thanks for the reply.

The ones in the photo are just loose laid for demonstration purposes to show what I wanted to do.

The project is DIY at home and I had previously cast the concrete steps earlier in the year without giving much thought to what I was going to use as a finished surface. Having started to lay block paving at the top and bottom of the steps in marshalls tegula I thought it would be good to have steps to match!

I have today tried a few offcuts onto the concrete with various mixtures of sand and cement and PVA. I also toyed with the idea of mechanically fixing an aluminium "L shaped" extrusion to the nose of each step and angle grinding a groove on the underside of the blocks that will sit on the front edge to act as a horizontal restraint!If I can get a good fix along with the front edge of the step then the others behind could be laid on sand as normal.

I will have a look at the tile adhesives available, although this might work out expensive.

The main thing I was worried about was resistance to freezing in the winter with any particula bond so I wondered if you guys had come across this sort of situation on a professional job.

Thanks again for your reply.

[Tony McC]

SBR mortar - mix a Class II mortar and add SBR/Ronafix as per manufacturer's instructions to create a mortar that will *never* let go of the blocks!

[Mark9691]

Thanks Tony,

A Builder suggested just the same (with ronafix); unfortunately after I had already started attaching with the external tile adhesive as suggested above.

I am using the adhesive on the sides of the uprights and also btw the edges of the blocks on each nosing so hopefully when finished it should be quite a strong fix.

The concrete steps were already flat and set out accurately when cast, so a thin bedding can be used and the adhesive goes a long way.

Thanks again for your help and I will use ronafix next time?When these fall off!
:laugh:

[Tony McC]

If you've used exterior grade tile adhesive, they should be OK, but laitence on the concrete substrate can be a problem. Laitence can be thought of as a very thing manky crust that forms on concrete surfaces. When bonding anything to concrete, best practice is to "etch" the surface with a strong hydrocholric acid to remove any laitence and expose a 'fresh' surface that will form a good key with the overlying mortar.

If you've any more of this type of work to do, then give serious consideration to etching and using a SBR/Ronafix improved mortar as it will give a more reliable finish than tile adhesive.