Cedar Siding Repaint with Rain Coming
You are estimating an exterior repaint of a two-storey cedar-sided house with 240 m² of wall area, 16 windows, and four exterior doors. The existing finish is a semi-transparent oil stain that is chalky and peeling on the south wall; the north wall is sound but faded. Moisture meter readings are 14–16% on the north wall and 22–28% around two south-facing window heads. One sill is soft when probed with an awl. The forecast calls for a 60% chance of rain in 36 hours, followed by three dry days. The client wants a solid latex stain in a dark green, 'two coats, no primer.' Your crew of three includes one first-year apprentice. Company production data: brush-and-roll application averages 5 m² per painter-hour per coat; stain covers 8 m² per litre per coat; prep is estimated at 12 crew-hours. The client wants the price by tomorrow.
1. Which parts of this house should not be coated in the next weather window, and what checks must you complete before finalizing the estimate?
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The south wall and the two window heads are the critical no-go areas. Readings of 22–28% are too high for most exterior latex stain systems; wood often needs to be below about 15–18%, and the coating data sheet governs. The soft sill indicates decay or hidden moisture, so it cannot be painted as-is.
Before pricing:
- Probe the sill and adjacent trim; if soft, price replacement or consolidation, not paint.
- Check the source of water at the window heads: failed caulk, flashing, or gutter. Coating over active water is a callback.
- Take moisture readings on bare wood, not just the old film; compare north and south exposures.
- Do a test patch on the north wall and a dry south area to check adhesion, tannin bleed, and whether the dark green will cover in two coats.
- Confirm rain timing: a 60% chance in 36 hours means the south wall likely cannot receive two coats in this window. Do not coat if rain is expected before the coating has set.
I would exclude the wet south wall and sill repair from the firm price, or list them as provisional sums, and state the moisture and weather conditions in the proposal.
2. Calculate the painter-hours and material for two coats on the 240 m², ignoring openings, and explain how you would present the estimate given the weather risk.
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Ignoring openings: 240 m² × 2 coats = 480 m² of coating.
Labour: 480 m² ÷ 5 m² per painter-hour = 96 painter-hours. With three painters, 96 ÷ 3 = 32 hours each, or four 8-hour days, plus 12 crew-hours of prep (4 hours per painter). That is about 4.5 days of good weather, not counting masking and cleanup.
Material: 480 m² ÷ 8 m² per litre = 60 litres. Add 10% for waste, touch-up, and roller loss = 66 litres. If bare wood or repairs are primed, add primer separately; do not hide it in the two-coat figure.
Presentation: price the sound north and east walls as firm, and the south wall as provisional pending moisture and repairs. Include a weather day or a clear note that rain delays are extra. State that the dark green may need a primer or a third coat for uniform colour, and that the client's 'no primer' instruction is accepted only for sound, previously coated areas. Offer a test patch and a revised price after the sill is opened.
3. Outline the application sequence and the specific conditions you would enforce on site.
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Sequence: wash all surfaces to remove chalk; scrape loose stain; sand edges; HEPA-vacuum and wipe dust; treat any mildew with an appropriate cleaner and rinse; repair or replace the soft sill; caulk joints with a paintable exterior sealant; spot-prime bare wood and repairs with a stain-blocking exterior primer.
Application: apply two coats of the specified solid latex stain at the manufacturer's spread rate, back-brushing or back-rolling to work it into the grain. Maintain a wet edge and follow the same direction on each board. Do not apply in direct sun on a hot south wall, or if rain is expected before the recommended dry time. Check surface temperature, not just air temperature.
Site rules: moisture below the coating's limit; no coating over active moisture; no thinning unless the data sheet allows; keep the apprentice on prep and masking until competent; record batch numbers and weather. If the south wall stays wet, leave it and schedule a return rather than risking a peel.