Problems with Masonry




Mouldy Brickwork

Mouldy brickwork is often caused by penetrating damp that is getting into the exterior substrate.

If an exterior substrate has issues with mould, treat with fungicide wash or a mould resistant primer. Proceed with applying masonry paint.


New brickwork or stonework should be left for at least three months before any treatment is applied. During this time a white powdery substance may seep out of the bricks, stone or cement. This is caused by the water dissolving the salts found within all of these materials. If Efflorescence appears on older brickwork, it is often a sign of excess moisture, and the source of the damp needs to be found before it is treated.

Clean excess efflorescence with a wire brush then coat with a weatherproof exterior masonry paint to prevent excess water getting into the masonry. Ensure to use masonry paint is breathable so that any remaining damp isn’t trapped inside the masonry.

Cracked Stone Blocks

Often due to structural movement, common in older houses. Although some cracks can be fixed, be wary that too many cracks point towards bigger problems such as subsidence. There are two main kinds of vertical cracking in masonry: those that run straight down and stepped cracks that follow the mortar joints in a zigzag pattern. Less commonly cracks may also run horizontally. The other causes of Cracked Stone Blocks are: thermal movement, differential movement, Water and rust, doors and windows, shallow foundations, trees and bad building work.

In any case of cracked stone blocks , both thermal and differential movement needs to be accommodated and this can be done by forming an expansion joint with a flexible mastic sealant. You must also notify your local building control department in advance of all structural works. When the crack has been stabilised, stepped cracks can be re-pointed with a suitable mortar or using clear, flexible mastic. Vertical cracks will need to be replaced.

Damp Stone Blocks

Dampness in one form or another is not particularly unusual. There are several possible causes, often with more than one working in unison. For example, Driving wind and rain can penetrate solid walls where mortar joints are badly eroded. Blown faces of brick or stonework, and cracked or loose render, can absorb rainwater like blotting paper.

First deal with any rogue sources of water, such as leaks from gutters or pipe work. Where mortar joints have become seriously eroded, they will require raking out and re-pointing with an appropriate mortar mix and style. Ensure to use a breathable material to fix your wall to ensure the damp doesn’t remain trapped. When fixed, apply weatherproof masonry paint for extra protection.

Cracked Peeling Walls

Paint can crack and flake which sometimes exposes the exterior substrate. If dry paint splits even through one coat this can lead to a complete failure of the paint. Early on the problem appears as hairline cracks, followed by flaking. This can be caused by low-quality paint on the surface with inadequate adhesion and flexibility, paint spread too thin upon application, poor priming and also painting in cool or windy conditions.

If the cracking does not go down to the substrate, you may be able to correct it by removing the looser or flaking paint with a scraper or wire brush. Sand the area, prime any bare spots and repaint. However, if the problem exposes the substrate, remove all of the paint and re-prime and repaint with quality exterior masonry paint.

Render Failure

High levels of damp within the walls are often the likely cause of render failure. Moisture and frost can become trapped between the wall and the render first causing hairline fractures, and if left untreated the failure of the render. This can cause decay and damp to the interior of the building.

In most cases, only localised repairs will be required, and the first job is usually to hack off any hollow, loose and/or cracked render. This will expose bare patches of wall which will need time to dry out before new render is applied. Ensure your new render is correctly protected and weatherproofed.

Rust on Brickwork

Accidental damage

If rusty spots appear on your bricks, you need to clean them promptly as rust can spread and cause your brick to start deteriorating. You can get your bricks rust free again by using common household products or special rust-removing chemicals. Start with the mildest cleaning product and work your way up to harsher chemicals. We would recommend using the: Rust-Oleum cleaner/degreaser.


Purposeful damage

If graffiti occurs try cleaning the problem off the masonry using a power washer. However, it is best to pre-empt such a problem, by applying a product like the Pegagraf-Hydro Anti Graffiti Coating before the issue occurs. Then, if Graffiti does appear simply apply Pegagraf-Hydro Cleaner for easy removal of any graffiti vandalism.


Compare 0