Which Primer and adhesive to use with Wedi and breeze block

[cooa99]

Hi all,

I have stripped tiles and plasterboard off my bathroom and was hoping to use a Wedi(I think) board around the bath tub. The longer wall by the bath has grey breeze block with the previous plasterboard attached with dot and dab. I am not sure what the difference between breeze block and Thermalite is ..... but it's a very soft brick....

My limited understanding is that the breeze block needs to be primed first before attempting to fix a waterproof board. I was wondering if you can recommend a primer that can be used.

Please can you also recommend adhesives that I can use to stick the Wedi board to the wall.

Thanks very much

 

[Swwils]

Let's clarify the difference between breeze blocks and Thermalite blocks. Breeze blocks are typically made from concrete and aggregates like ash, hence the name. They are commonly used for structural walls due to their durability and strength.

On the other hand, Thermalite blocks are a type of aerated concrete block, primarily used for their excellent insulation properties. They are lighter and easier to cut than breeze blocks, but also softer and can be less durable.

In your situation, as the breeze blocks you're dealing with are described as soft, they could potentially be Thermalite or another type of aerated concrete block. This can matter when selecting primers and adhesives.

When preparing your blocks for tiling, using a primer can indeed help to create a more secure bond. SBR (styrene-butadiene rubber) is a commonly used primer that would work well in this situation. SBR primers work well to reduce the absorbency of the blocks and aid in adhesive bonding.

As for fixing Wedi board to the wall, Wedi recommends using their own brand of adhesive/sealant called Wedi 610. This product is specifically formulated for adhering their boards to various substrates, ensuring a strong bond and full waterproofing capabilities.

However, if Wedi 610 isn't available, you can use a cement-based flexible tile adhesive. Be aware that while this can provide a good bond, it may not give the same level of waterproofing as the Wedi 610, so it's best to use Wedi 610 if possible.

Remember to also tape and seal all board joints with Wedi joint sealant and Wedi reinforcement tape to ensure complete waterproofing

 

[cooa99]

Let's clarify the difference between breeze blocks and Thermalite blocks. Breeze blocks are typically made from concrete and aggregates like ash, hence the name. They are commonly used for structural walls due to their durability and strength.

On the other hand, Thermalite blocks are a type of aerated concrete block, primarily used for their excellent insulation properties. They are lighter and easier to cut than breeze blocks, but also softer and can be less durable.

In your situation, as the breeze blocks you're dealing with are described as soft, they could potentially be Thermalite or another type of aerated concrete block. This can matter when selecting primers and adhesives.

When preparing your blocks for tiling, using a primer can indeed help to create a more secure bond. SBR (styrene-butadiene rubber) is a commonly used primer that would work well in this situation. SBR primers work well to reduce the absorbency of the blocks and aid in adhesive bonding.

As for fixing Wedi board to the wall, Wedi recommends using their own brand of adhesive/sealant called Wedi 610. This product is specifically formulated for adhering their boards to various substrates, ensuring a strong bond and full waterproofing capabilities.

However, if Wedi 610 isn't available, you can use a cement-based flexible tile adhesive. Be aware that while this can provide a good bond, it may not give the same level of waterproofing as the Wedi 610, so it's best to use Wedi 610 if possible.

Remember to also tape and seal all board joints with Wedi joint sealant and Wedi reinforcement tape to ensure complete waterproofing

Thanks very much. I understand that I also need to screw the board to the wall as well.

The bath will be in the corner against 2 walls. Should the Wedi board go from floor to ceiling or above the bath? This will make a difference to if only the tiles or tile & board overhangs on the edge of the bath

Thanks

 

[Mr Chibs]

You should be able to use 'primer g' for this. Looks like a glorified PVA, and helps with bonding a substrate to the next one.

You can glue wedi boards to the wall, but you would be advised to put some mechanical fixings/screws into the wall, in case the glue is not sufficient. Insulation washers can be used with screws and plugs or concrete screws.

Lightweight blocks, look the inside of a Cadburys wispa bar, but cement grey in colour. If you have these, then you may need to get suitable rawl plugs, but these are easy to get from screw fix/tool station.

 

[cooa99]

I can get the ones they recommend. Just looked at prices and its a bit steep compared to hardie board especially when looking at the 2500 tall ones.

I’m now wondering if i should take a chance on them. The previous plasterboard I took out had been there 20yrs without any damage. They house builders must have tanked it very well

 

[Swwils]

Wedi boards are worth the premium if ease of cutting, complex bathrooms, humidity levels, ease of handling, speed of installation are important to you or your project.