Stormdry No1 breathable water repellent additive for mortar 500ml

Stormdry No1 breathable water repellent additive for mortar 500ml

Write a review



Test Category

No Downloadable

No Specification

Play Videos

full view icon

A concentrated liquid that is to be used as a diluted part of the gauging solution in sand and cement mortar. It is used for repointing before a Stormdry Masonry Protection Cream application. Stormdry Repointing Additive No.1 enhances the waterproofing qualities of a standard sand and cement mortar mixture whilst still allowing it to breathe.

Each 500ml bottle will usually be sufficient to repoint 5m2 of brickwork

Price is per bottle

Ecomerchant Stormdry BBA logo




full view icon

When penetrating damp occurs, the cause is often a mixture between porous building materials and degraded pointing.

Testing done by our research and development laboratory has shown that on a brick wall, at high water pressures, a large amount of water penetrates through the join between the mortar course and bricks.This is because, over time, small cracks and defects in the pointing can appear, creating pathways which moisture can transfer. This is due to a multitude of factors, including shrinkage of the mortar, freeze / thaw damage and simple weather erosion.

The solution to this problem is to repoint the wall using the appropriate Stormdry Repointing Additive.

Usually, a combination of repointing and a treatment of Stormdry Masonry Protection Cream is the ideal solution. It may only be necessary to repoint localised sections of a wall before treatment. If the mortar is in particularly bad condition, however, it may be required to repoint the entire wall to before the full Stormdry treatment.

A certain amount of repointing will usually be necessary when dealing with rain penetration problems in masonry walls. This is because small cracks in the mortar course and cracks in the interface between the mortar and brick/stone can acts as pathways through which rain can penetrate. In many cases, only localised sections of mortar will require repointing. However, where the mortar is in particularly poor condition it may be necessary to repoint the whole wall.

Stormdry Repointing Additives are designed to enhance the waterproofing characteristics of mortar mixes used for repointing. They are diluted with water before being used as a gauging solution. Two types are available:

Stormdry Repointing Additive No. 1 - This contains a blend of silanes and siloxanes (similar to those found in Stormdry Masonry Protection Cream). These block water ingress whilst still allowing the mortar to breathe.

Stormdry Repointing Additive No. 2 - This repointing additive is polymer modified giving allowing it to impart excellent waterproofing characteristics to repointing mortars and enhanced bonding characteristics between the brick/stone and the mortar. Unlike Stormdry Repointing Additive No. 1 this additive does not allow the mortar to breathe.


 Stormdry Repointing Additive No.1 Properties
White/milky liquid
Size(s) & Packaging 
 500 ml bottles
One 500 ml container will provide sufficient mortar to repoint an area of 5 m2 of masonry.
Store in a cool, well ventilated area. Keep container tightly closed. Protect from frost
Shelf Life  
 12 months


Write Your Own Review

You're reviewing: Stormdry No1 breathable water repellent additive for mortar 500ml

How do you rate this product? *

  1 star 2 stars 3 stars 4 stars 5 stars

Regular Price: £25.00

Special Price £21.50

Per Bottle

Availability: In stock