How to prepare your house exterior for painting

Washing, scraping, repairs, caulking and primer: the prep that decides how long exterior paint lasts.

A painted blue porch with a black door

October 23, 2026 · 4 min read · By Pulkit Homes

Quick answerExterior prep before painting usually means washing the surfaces, scraping loose paint, repairing damaged wood or siding, caulking gaps and priming bare spots. Skipping these steps is the main reason exterior paint peels early, so prep is worth as much as the paint itself.

The best exterior paint in the world fails on a dirty, damaged surface. Most of the work in a good exterior job happens before the first coat goes on.

Key takeaways
  • Wash off dirt, mildew and chalk
  • Scrape and sand loose paint
  • Repair damaged wood and siding
  • Caulk gaps and joints
  • Prime bare spots before painting

Washing

Dirt, mildew and chalky residue stop paint from bonding. Washing the walls and letting them dry thoroughly removes them. Near trees, shade and damp can leave green growth that needs cleaning first.

Scraping and sanding

Loose, peeling or blistered paint is scraped back to a solid edge, and rough edges are sanded so they don’t show through. On an older house, scraping may disturb lead paint, so it’s handled with care. Read our guide to lead paint in older homes.

Repairs and caulking

Rotten or damaged wood is repaired or replaced, nail holes are filled, and gaps around windows, doors and trim are caulked. Caulking keeps water out, which protects both the paint and the structure.

Priming

Bare wood and repaired spots are primed so the topcoat sticks evenly and the repairs don’t show. A good primer is cheaper than repainting early, and it’s one of the steps people most often skip.

Timing the prep

Prep needs dry weather as much as painting does, so it happens in the same season. Read our guide to the best time to paint your exterior. Exterior work is quoted after a visit, so we can see what the surfaces need.

Quick questions

Can I pressure wash my own house?

Pressure washing can damage siding and force water behind it if it’s done too hard. Gentler washing is often enough, and an experienced painter knows the right approach.

How long should I wait after washing?

Surfaces must be completely dry before painting. That can take a day or more, depending on the weather and the material.

Planning an exterior job? Contact us and we’ll arrange a visit to see what your house needs.

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