Why Exterior Damp Proof Paint is Bad For Your Home
Damp proof paints and renders contain plastics which form a waterproof seal when applied to a wall. They’re ideal for modern buildings, but can have disastrous impacts on period properties.
You may think that completely stopping any water entering your home is the best way to prevent damp, but the opposite is true when it comes to solid brick buildings.
Yes, you’ll stop rainwater from entering the wall, but you’ll also stop interior moisture from escaping. This leads up a build-up of moisture inside the walls, resulting in severe damp and mould.
Book Appointment
Live Chat
Email UsWhy can’t I use waterproof paint on a solid brick wall?
The reason bricks were our favourite building material for hundreds of years is their breathability. Moisture is absorbed and then evaporates through their sponge-like structure, which prevents build up of damp.
Modern buildings are designed so that no water passes through the main structure and interior moisture is entirely controlled through ventilation.
Old buildings with solid brick walls work very differently. Bricks act like a sponge, absorbing and then releasing moisture through their porous structure. This works the same way whether it’s exterior moisture from rain or interior moisture from cooking, cleaning or laundry.
This is known as the building “breathing”, and allowing brick walls to behave as they’re supposed to is key to preventing the build up of damp and mould.
But I don’t want to live in a draughty house
Don’t confuse moisture evaporation through brickwork with air passing through your walls. A building can be completely sealed against cold draughts while still allowing the brickwork the breathe.
This is the correct approach to controlling temperature and moisture in a period property without interfering with the natural breathability of bricks.
Of course, you still need ventilation to get rid of stale air and prevent excessive moisture build up and condensation. Ventilation can be easily installed for a pennies-a-day running cost with a PIV unit.
Learn more about PIV unit installation.
If I can’t use waterproof paint on the exterior, how do I stop water getting in?
Damp can enter your home from the outside, known as penetrating damp. But the solution to penetrating damp isn’t to completely seal up the exterior wall, it’s to repair it to a high quality.
Penetrating damp isn’t caused by natural water absorption of bricks, it’s caused by cracks in brickwork or pointing which allows water to seep into the building. These cracks widen over time through erosion and freeze-throw damage.
You should regularly have the outside of your building inspected for cracks or decayed pointing so that they can be repaired before penetrating damp develops.
Book Appointment
Live Chat
Email UsI Need a Carpenter Near Me
Finding a reliable carpenter in London is a challenge. Don’t waste time trawling through ads on Gumtree, give Environ a call for picture perfect carpentry from a family run London company. Whether...
A Guide to Section 20 for Freeholders and Landlords
What does Section 20 mean for freeholders, property managers and landlords? Section 20 doesn’t make a distinction between landlords, freeholders, Right to Manage Companies, Resident’s Management...
A Guide to Section 20 for Leaseholders
What does Section 20 mean for leaseholders? Section 20 considers freeholders, Resident’s Management Companies, Right to Manage Companies or any other property managers with freehold responsibilities...
Should I Paint Over My Damp Walls?
One of the most common and costly DIY mistakes is trying to paint over walls or ceilings suffering from damp and mould. Before long, the paint is bubbly, peeling and mouldy again – your money wasted...
What is Lateral Damp?
Lateral damp is when groundwater penetrates sideways into a property through cracks or porous building materials. It can affect any floor which is in contact with soil, but is most common in...
What Causes Lateral Damp?
When soil presses against a wall that is cracked or made from porous materials, groundwater can seep through and saturate the wall, causing lateral damp. You’ve probably seen lateral damp on a small...
What is Penetrating Damp?
Penetrating damp is damp which has entered the property from the exterior or from leaking plumbing. This also known as water ingress. If water is entering a wall, floor or ceiling at a faster rate...
What Causes Penetrating Damp?
Do I have penetrating damp Penetrating damp is caused by water entering a wall, ceiling or floor from outside the building or from leaky plumbing. A wide variety of exterior defects can allow water...
Why is My Basement Damp?
In London, it can be difficult to find the room or get permission to extend your property. This means that more and more people are turning to their basements for extra space. But no one wants to...
