Waterproofing a facade: DIY or professional?

Short answer: impregnating makes a porous facade water repellent while the wall can still breathe. It helps against a facade that turns dark and wet in the rain, against green growth and against frost damage. It does not help with cracks, damaged pointing, leaking gutters or moisture coming from inside or from below. You can impregnate a low, easily reachable wall, a garden wall or part of a facade on the ground floor yourself. If the facade is high, the pointing is poor or the cause of the moisture is unclear, call in a professional.

Read this article in Dutch as well: Buitenmuur of gevel impregneren: zelf doen of vakman?.

What does impregnating actually do?

An impregnating agent penetrates the pores of brick, natural stone, concrete or sand-lime brick. It does not form a layer on the surface like paint. Rainwater beads off, but water vapour from the wall can still escape. A product such as Fila Hydrorep Eco water repellent is water repellent, breathable and leaves no sheen. Check the product page and the label to see which surfaces a product suits.

DIY or professional?

👷 A facade specialist or pointer first looks at the cause of the moisture. Is it driving rain, a leaking gutter, damaged pointing or rising damp? Impregnating only makes sense on a healthy facade. That diagnosis and repairing the pointing are craftsmanship you do not skip. Also read our blog on cleaning gutters: DIY or professional.

Check first

1. Gutters and downpipes. An overflowing gutter soaks a facade with every shower. Solve that first.
2. Pointing and cracks. Scratch the joint with a key. If it crumbles or has holes, it needs repointing first.
3. Connections. Sealant around frames and penetrations must be intact. Repair joints with a grainy facade acrylic sealant and let it cure before you impregnate.
4. Moisture in the wall. A Hydromette Compact B moisture meter shows whether the wall is dry enough. A wet wall does not absorb the product well.
5. The weather. With an air humidity and temperature meter you keep an eye on humidity and temperature. Work after a few dry days, with a dry forecast, above about 5 degrees and not in full sun or strong wind.

⚠️ In autumn and winter the facade is often too wet and too cold. Use these months to inspect and repair, and plan the impregnation for a dry period in spring or summer.

How to impregnate a low wall

1. Clean the facade. Remove green growth, dust and dirt and let the wall dry thoroughly. For mould indoors read our blog on removing mould from walls.
2. Cover up. Protect glass, frames, doors and plants with masking film and exterior masking tape. Lay a tarpaulin of 3 x 5 metres on the paving below.
3. Test a sample area. Treat a small area and check after drying that the colour does not change.
4. Apply the product. With the impregnation set or a 1.5-litre hand pressure sprayer or 2-litre hand pressure sprayer, apply the product wet-on-wet, from bottom to top, until the stone is saturated. Follow the label for the number of coats and the waiting time.
5. Let it dry. Keep the wall dry for a day. The water-repellent effect is at its best once fully cured.

Working safely

Wear safety goggles and work gloves with nitrile coating, because spray mist quickly gets into your eyes and onto your skin. When spraying in a windy spot or for longer jobs an FFP2 dust mask is useful. Read the safety data sheet for the right mask. Work on a stable folding ladder with handle and never with one hand above your head. If you need to go higher than you can safely reach with a household ladder, you need scaffolding with a safety helmet and, when working at the edge, a safety harness. That is a job for a professional. Also read our blog on safe working on the construction site.

Frequently asked questions

How long does an impregnation last?

That differs per product and per facade. The label gives an indication. When you see that water no longer beads off, it is time for a new treatment.

Can I impregnate a painted wall?

No, the product has to soak into the stone. Impregnating does not work on paint or a closed coating.

Does impregnating help against damp inside?

Only if the moisture comes from driving rain outside. With rising damp, leaks or condensation the cause lies elsewhere. Have that investigated first, and for storm damage read our blog on checking your roof after a storm. To get the whole house ready for the cold, see our blog on getting your home ready for winter.

Where can you find everything for this job?

At Saniso, the online store for DIYers and professionals, you will find tools, materials and personal protective equipment for your job.

• Browse our construction tools and our workwear and safety.
• Create a customer account and order easily.
• Working on a bigger project or want to hand over the job? Request a project quote.
• Book a showroom visit, at least 24 hours in advance.
• Not sure which material suits your job? Get in touch with us.

In doubt about the approach? Feel free to call in a professional.

Saniso – Build your home with Saniso.