How to Seal Exposed Brickwork Inside Your Home to Reduce Dust

Exposed brick inside a home looks great, but unsealed brickwork can shed fine dust and grit onto furniture, floors, and soft furnishings. The good news is that sealing interior brickwork is a manageable DIY job for most homeowners — provided you choose the right product and prepare the surface properly first.

Why Exposed Brick Gets Dusty

Brick and mortar are naturally porous materials. Over time — especially in older NZ homes where bricks may have never been sealed — the surface gradually breaks down, releasing fine particles of sand, clay, and mortar dust. This is made worse by:

• Moisture cycling — humidity and temperature changes cause the brick to expand and contract
• Age and weathering — older bricks are often softer and more friable
• Mechanical disturbance — brushing against the wall or vibrations from foot traffic

Sealing the surface binds those loose particles and creates a protective layer that stops further dusting.

Step 1 — Assess the Brickwork First

Before reaching for a sealer, take a close look at the wall:

• Check for efflorescence (white salt deposits) — this needs to be treated before sealing, or it will be trapped and cause the sealer to fail
• Look for crumbling mortar joints — these should be raked out and repointed before sealing
• Check for damp or moisture coming through the wall — sealing over a damp wall can cause blistering and peeling

If you spot significant structural issues, cracked bricks, or ongoing moisture problems, it's worth getting a qualified bricklayer to assess the wall before you do anything else. You can find experienced local bricklayers on tradedirectory.co.nz.

Step 2 — Clean the Surface Thoroughly

Good preparation is the most important part of the job. A sealer applied to a dirty or dusty surface won't bond properly.

1. Brush down the entire wall with a stiff-bristled brush to remove loose dust, cobwebs, and debris
2. Treat efflorescence — scrub affected areas with a diluted solution of white vinegar or a proprietary efflorescence remover, then rinse and allow to dry fully
3. Allow adequate drying time — in NZ's more humid regions (Northland, West Coast, parts of Auckland), allow at least 48–72 hours after any wet cleaning before applying sealer
4. Vacuum the wall surface with a brush attachment to pick up any remaining fine dust

Step 3 — Choose the Right Sealer

For interior brickwork, you have a few main options:

For most interior dust-reduction jobs, a penetrating acrylic or clear masonry sealer works well. Brands like Resene and Dulux both offer masonry sealers suited to interior use — check their product guides or ask in-store for their current interior masonry range. Wattyl also offers masonry coating products worth considering.

Always read the product data sheet and confirm the product is suitable for interior use — some exterior sealers have strong solvent fumes that are not appropriate for enclosed spaces.

Step 4 — Apply the Sealer

1. Protect surrounding surfaces — lay drop sheets and mask off skirting boards, floors, and adjacent walls
2. Ventilate the room — open windows and doors; use a fan if needed, especially with solvent-based products
3. Apply with a brush or roller — a thick-nap roller (18–20 mm) works well for textured brick; use a brush to work sealer into mortar joints
4. Work in sections — apply evenly, working from top to bottom to catch any drips
5. Apply a second coat — most manufacturers recommend two coats; check the product's recoat time (typically 2–4 hours for water-based products)
6. Allow full cure time before moving furniture back — usually 24–48 hours

Safety note: Even water-based sealers can cause skin and eye irritation. Wear gloves, safety glasses, and ensure good ventilation throughout the job. For solvent-based products, check the safety data sheet — WorkSafe NZ has guidance on working safely with chemical products.

What to Expect After Sealing

A good quality sealer will significantly reduce dusting and make the wall much easier to wipe down. Depending on the product and the condition of the brick, you may need to reapply every few years. Penetrating sealers generally last longer than surface-film products on rough, textured brick.

Note that sealing will not fix structural problems — if mortar joints continue to crumble or bricks are spalling, the underlying issue needs to be addressed.

When to Call a Professional

Consider calling a qualified bricklayer or stonemason if:

• Mortar joints are crumbling or missing in multiple areas (repointing is needed first)
• Bricks are cracked, spalling, or structurally compromised
• There is ongoing moisture or damp coming through the wall
• The wall is part of a structural or load-bearing element — any work affecting structural masonry may require a building consent; check with your local council and refer to MBIE Building Performance for guidance on consent requirements
• You're unsure about the type of brick or mortar (some heritage bricks require specialist products)

For painting or coating work on a larger scale, a qualified painter familiar with masonry substrates can also help. Find trusted local tradespeople at tradedirectory.co.nz.

Sources & Further Reading

• Resene — Masonry & Concrete Coatings
• Dulux NZ — Exterior & Masonry Products
• WorkSafe NZ — Working Safely with Hazardous Substances
• MBIE Building Performance — Building Consent Information
• BRANZ — Building Research