Stopping Penetrating Damp: Clear Water Repellents Explained

You have damp patches on your internal walls. They aren't near the floor (Rising Damp), and they aren't near the ceiling (Leaking Roof). They are floating in the middle of the wall, usually appearing darker after heavy rain. This is Penetrating Damp.

It happens when your exterior brickwork becomes porous. Like an old sponge, the bricks absorb rainwater. When the wall becomes fully saturated, that water travels through the solid masonry and ruins your interior plaster, wallpaper, and paint. You can't just paint over the damp inside; the moisture will eventually degrade the paint until it flakes off. You need to stop the water from getting in on the outside. But you don't want to paint your lovely brick house with coloured masonry paint.

You need a Clear Water Repellent. Here is how to waterproof your walls without changing their appearance using SummitSeal - BRICOAT.

1. The Science: Why Bricks Leak

Bricks are inherently porous. They are designed to absorb a little water and then dry out in the wind. However, as bricks age, the "face" erodes, and the mortar joints become crumbly and absorbent.

• The Sponge Effect: A standard house brick can hold up to 200ml of water. If you have thousands of bricks, your wall can hold tonnes of water after a storm.

• The Thermal Penalty: Wet walls are cold walls. Damp masonry transfers heat out of your house 3x faster than dry masonry. So, penetrating damp isn't just ruining your décor - it is increasing your heating bill.

2. The Solution

Previously, people used to use varnish-style surface sealers. These formed a shiny plastic skin on the brick. However, we strongly urge against this. This type of sealer traps moisture inside the wall, causing the brick faces to spall (blow off) when it freezes.

You need a Breathable Impregnator like SummitSeal - BRICOAT. This uses advanced resins to treat the brick internally, while still allowing moisture the escape the brick.

• Penetration: It doesn't sit on the surface. It soaks deep into the capillaries of the brick (up to 10mm deep).

• Water Resistance: It lines the microscopic pores with silicone. When rain hits the treated brick, the water beads up and rolls off instead of soaking in.

3. Breathability is Non-Negotiable

This is the most critical part of this system. Your house produces moisture inside (cooking, showering, breathing). That moisture needs to escape out through the walls. If you seal the outside with a non-breathable coating, the internal damp gets trapped in the wall, leading to black mould and condensation.

SummitSeal - BRICOAT is fully breathable:

1. It stops liquid water (rain) from getting in.

2. It allows water vapour (gas) to get out. It works exactly like a high-end Gore-Tex waterproof jacket - keeping the weather out while letting the building breathe.

4. Why Use a Liquid Impregnator?

While there are various methods to seal a wall, a high-quality liquid impregnator offers specific advantages for the DIYer and professional alike.

• Ease of Application: Liquid sealers can be applied rapidly using a low-pressure garden sprayer or a masonry roller. This makes treating large elevations much faster than trowel-applied methods.

• Deep Saturation: Because the fluid has a low viscosity (it is thin like water), it is sucked deep into the brickwork by capillary action immediately upon contact. It doesn't sit on the surface waiting to absorb; it dives straight into the pores.

• Cost-Effective: Liquid impregnators provide excellent coverage rates, making them an economical choice for treating entire houses.

5. Application Tips for Success

To get the best out of SummitSeal - BRICOAT, follow these three rules:

Rule 1: Repoint First A water repellent is a sealer, not a filler. It cannot bridge a physical hole. If your mortar is missing or the bricks are cracked, fill these defects first and let the mortar dry.

Rule 2: Dry Walls Only Do not apply to a wet wall. If the pores of the brick are already full of rainwater, they cannot accept the sealer. Wait for a dry spell of at least 48 hours before applying.

Rule 3: Protect the Glass Silicone-based sealers are excellent at bonding to masonry, but they can etch glass or stain window frames if left to dry.

• Mask off your windows before spraying.

• If you do splash the glass, wipe it immediately with a soapy cloth before it dries.

Conclusion

Penetrating damp is not just a cosmetic issue; it destroys your home's insulation and rots structural timbers. By impregnating the brickwork, you keep the wall dry. A dry wall is a warm wall. It is the invisible shield your home needs against the British weather.

• Check the pointing

• Wait for a dry day

• Apply the Impregnator

Ready to stop the damp?

→ Shop our SummitSeal - BRICOAT - Impregnating Brick Sealer