How do I know when I have scraped enough?

When the scraper, pulled firmly, stops lifting paint. A strip of strong tape pressed onto the scraped edge and pulled off sharply is a useful check: if paint comes away on the tape, the edge is still loose. The goal is a sound edge all around, not bare wood everywhere.

Do I need to sand the whole surface or just the edges?

Usually the edges and the glossy areas. The ridges where old paint meets bare wood are feathered smooth so they do not telegraph through the new paint. Glossy old paint is scuff-sanded so primer can grip. Sound, dull paint between those areas generally needs only cleaning.

What is alligatoring, and can it be scraped?

Alligatoring is a pattern of deep cracks in old paint that looks like reptile skin, usually from many incompatible or heavy coats. The cracks go down through the layers, so it cannot be feathered smooth. The failing coating is removed down to a sound layer or bare surface.

Is it safe to sand paint on an older house?

On homes built before 1978 the old layers may contain lead, and dry sanding or power sanding without proper controls spreads lead dust. Federal EPA rules restrict how paid contractors disturb that paint, including power sanding without a shroud and HEPA dust collection. Ebenezer is EPA lead-safe (RRP) certified, and he finds out what is on the walls before any scraping or sanding begins.

Scraping and Sanding Peeling Paint

Peeling paint is scraped until only paint that is firmly attached remains, then the hard edges between old paint and bare surface are feathered with sandpaper so they do not show through the new coat. Glossy areas are scuffed, dust is removed, and any bare wood is primed promptly, because bare wood left in the sun loses the surface paint needs to grip. On pre-1978 homes, the method changes.

Most of the work on a peeling exterior is not painting. It is taking off what has failed, so that the new paint goes onto a surface that will hold it, and then smoothing what remains so the old failure does not show through. Scraping and sanding are slow, dusty and unglamorous, and they are the steps that decide whether the new paint looks like a new finish or like old peeling painted over.

Why the paint peeled in the first place is its own question, covered in why exterior paint peels. This article is about what happens once the cause has been found and fixed.

Before anything is scraped: the age of the house

If the home was built before 1978, the older layers of paint may contain lead. Scraping, and especially sanding, turns that paint into chips and dust. It does not make the surface untouchable, but it changes the method, the containment and the clean-up, and the EPA’s lead rules apply to anyone paid to disturb it. Many homes in National City, La Mesa and the older neighborhoods of San Diego are that age. Ebenezer is EPA lead-safe (RRP) certified, so on a house that age the scraping and sanding are planned under those rules from the first day. Our article on lead paint in pre-1978 homes sets out the general facts.

What does “scrape to a sound edge” mean?

It means removing paint until every edge left behind is firmly attached to the surface. You do not need to strip the whole board to bare wood. You need to remove everything that is loose, cracked, blistered or lifting, so the new paint is not built on top of a failure that will let go again.

The scraping

Protect the ground. Drop cloths go down under the work area to catch chips, and the chips are gathered up rather than left to blow around the yard.
Use the right scraper for the surface. A sharp pull scraper does most of the work on flat wood; a stiff putty knife reaches into corners and profiles; a wire brush is for loose paint and rust on metal, not for wood.
Work with the grain on wood, pulling rather than gouging, so the scraper lifts paint without digging into the board.
Keep the blade sharp. A dull scraper skates over loose paint and tears into soft wood.
Test the edges. Strong tape pressed hard onto a scraped edge and ripped off sharply shows whether the remaining paint is truly attached. If paint comes away on the tape, keep scraping.

On textured stucco, peeling paint is removed with scrapers and stiff brushes, working carefully so the texture underneath is not damaged. Stucco that comes away with the paint has its own problem, and it goes on the repair list.

Feathering the edges

After scraping, every patch has a hard step where the remaining paint meets the bare surface. Paint does not hide that step; it outlines it. Under low sun, a wall with unfeathered patches shows every scrape as a crisp-edged island.

Feathering is sanding those steps down so they taper smoothly from bare surface up to the old paint:

A coarser grit first, to knock down the ridge, then a finer grit to smooth the transition.
Sanding blocks on flat boards so the surface stays flat, and hand sanding on profiles and molding, where a machine would round over the detail.
Where there are many thick layers, as on some old wood homes, sanding alone may not bring the step level. A suitable filler or high-build primer is used to fill the transition, then sanded smooth.

This is the kind of hand work that shows on the period homes in La Mesa, with their profiled trim and window detail, where the finish is judged at arm’s length.

Scuffing glossy paint

Sound but glossy old paint, common on trim and doors, gives new paint very little to grip. It is scuff-sanded to dull the surface and create a fine texture for the primer. Trim with old oil-based enamel needs more than a scuff, and painting over oil-based trim covers that in detail.

Sanders and dust

Power sanders save hours on large flat areas, but they are not always the right tool. They can round over crisp trim profiles, cut too deep into soft wood, and throw fine dust into the air. Where they are used, dust collection matters, and on any surface that may contain lead, power sanding without proper controls is not acceptable practice.

After sanding, all dust is removed. Paint over sanding dust bonds to the dust, not the wall.

Prime the bare wood promptly

Bare wood exposed by scraping should not sit in the sun for long. Ultraviolet light breaks down the surface fibers of bare wood surprisingly soon, and paint applied over that weathered layer does not hold as well. The usual practice is to prime bare wood soon after it is scraped and sanded, with a primer suited to exterior wood. Ebenezer uses Dunn-Edwards and Sherwin-Williams primers and paints, chosen for the surface they are going on.

When the whole coating has to come off

Sometimes scraping finds that nothing is sound. Alligatoring, a pattern of deep cracks like reptile skin, goes down through the layers and cannot be feathered. Widespread cross-grain cracking on wood with decades of heavy coats means the build-up can no longer flex. In those cases the failing coating is removed to a sound layer or bare surface. It is slow work, and it is the honest answer when the alternative is new paint over a failing base.

Why this matters for your estimate

Two houses with the same amount of visible peeling can need very different hours of scraping and sanding, depending on how many layers there are, how glossy they are and whether the house is pre-1978. Ebenezer prices by hours and prep difficulty for exactly this reason, and he will show you at the estimate where the scraping is and what it involves.

If your paint is lifting and you want it done properly rather than painted over, ask for a free estimate. He will walk the house, show you what needs to come off and how the surface will be brought back before any color goes on. More about exterior painting.