Aluminum & Vinyl Siding Painting in Toronto & the GTA

How can you tell if your siding is aluminum, vinyl or steel?

Two quick checks tell them apart: a fridge magnet, and a close look at a scratch or a cut edge. It matters because each material needs its own prep and paint.

Check	Aluminum	Vinyl	Steel
A fridge magnet	Doesn't stick	Doesn't stick	Sticks
A scratch or a cut edge	Bare metal under a baked-on finish	Plastic, coloured right through	Grey metal under the finish, sometimes with rust
What painting it involves	Chalk washed off, bare metal primed with a bonding primer	A colour no darker than the paint maker allows	Rust sanded back and primed with a rust-inhibiting primer

If you can't tell, say so when you send photos, and add a close-up of a scratch or a cut edge.

Why does the chalk have to come off before painting?

Because paint bonds to the siding only once the chalk is gone. Paint makers say a chalky surface must be cleaned before painting, and Benjamin Moore's siding paint data sheet ties it to adhesion.

Chalking is the fine powder left as sunlight breaks down the old finish. It is washed off with a detergent, by hand or with a pressure washer on a gentle setting, then rinsed and left to dry. A small painted test patch then shows whether the surface is ready for the whole house.

Our post on painting aluminum siding explains that adhesion test, how to check your own siding for chalk, and how painting compares with new siding.

Can vinyl siding be painted a darker colour?

Only in a colour from a paint maker's vinyl-safe range. Dark paint soaks up the sun's heat, and vinyl that expands too far may not shrink back to its original shape.

That is how painted vinyl warps and buckles. Sherwin-Williams' VinylSafe palette has 100 colours, including a limited selection of darker ones, for sound, stable vinyl. Benjamin Moore's data sheet for its vinyl siding paint offers hundreds of vinyl-safe colours. Outside those ranges, both makers say to go no darker than the siding's original shade.

The siding also has to be installed properly. Vinyl is meant to hang loosely on its fasteners, so it can slide as it heats and cools. Check the siding maker's own painting rules before you choose, since they can affect its warranty, as our post on painting vinyl siding notes.

How is overspray kept off windows, cars and gardens?

By masking what's near the walls, covering plants and watching the wind. Spraying lays paint on siding quickly and evenly, and back-rolling then works it into the surface. The catch is overspray, a fine mist that drifts past the wall.

• Masking. Windows, doors, lights, vents and fixtures on the wall are masked with paper and plastic before any spraying.
• Plants. Sprayer maker Graco advises covering plants and shrubs with plastic.
• Wind. Graco also advises noting the wind's direction, since wind carries the mist.

You can help too. Move cars away from the house on spraying days, and let close neighbours know when the work is planned.

How long does painted siding last?

There's no set number of years, because the sun, the prep and the paint decide it. On most houses, the south and west walls get the most sun and show wear first.

Here is what wear usually looks like on painted siding, and what it tends to mean:

What you see	What it tends to mean
Fading and a new film of chalk	Normal weathering from the sun, and a sign a repaint is coming
Peeling in flakes or sheets	The paint lost its bond, for example over chalk left underneath
Rippled or warped vinyl	Heat the vinyl couldn't take: a colour too dark, or panels fastened too tightly to move

Peeling, blistering and flaking caused by an application defect are what our written 3-year workmanship warranty covers. The warranty page sets out the terms, including what is not covered.