A decision you can check
- 01
Name the substrate
Record new drywall, previously painted plaster, wood, masonry or another surface. The coating data sheet should list it as an approved substrate.
- 02
Define the preparation
Cleaning, dulling gloss, repairing, sanding and dust removal are part of the system. Primer cannot make a weak or contaminated surface sound.
- 03
Match primer to the reason
Use a drywall primer, bonding primer or stain blocker only when the problem and finish manufacturer support it. Keep primer quantity separate from finish coats.
- 04
Lock the finish product
Record manufacturer, line, colour, base, sheen and expected coverage so the calculator and purchase order refer to one exact coating.
Write a specification someone else can check
Paint-and-primer marketing does not mean every stain, bare repair or adhesion problem can skip dedicated preparation.
Bathrooms and kitchens need ventilation and a coating approved for the exposure; simply choosing a shinier finish is incomplete.
- Name the substrate
- Define the preparation
- Match primer to the reason
- Lock the finish product
Convert the decision into quantities
Enter the measured geometry in the Paint Calculator, replace defaults with the selected product coverage and round only at the final purchasable unit. List accessories and preparation materials separately so a coverage change does not silently scale unrelated items.
For pre-1978 US homes, disturbing existing paint can trigger lead-safe renovation requirements.
Verify at order and delivery
Check the exact local designation or product code, performance class, size, colour or batch where relevant, stated coverage, yield, density or capacity, ordered quantity and accessory compatibility on the written order. Inspect delivered interior coating before installation and isolate damaged or mismatched material while return and replacement options remain open.
What usually throws the order off
- Choosing sheen from name alone
- Using primer instead of fixing a weak surface
- Combining primer and finish coverage
- Ordering before testing colour and light
Frequently asked questions
What must the interior coating specification identify?
Make the scope checkable against these decisions: name the substrate; define the preparation; match primer to the reason; lock the finish product. Record the exact local designation or product, performance class, dimensions, finish where relevant, accessories and controlling technical document.
Which calculator default changes after product selection?
Replace whichever default the exact interior coating controls—coverage, yield, density, dimensions, package quantity or capacity—while keeping the verified project geometry unchanged.
Who should approve a substitution?
The owner and responsible designer or installer should confirm in writing that the substituted interior coating preserves required performance, appearance, compatibility, installation method and documented supplier or project acceptance criteria.
Technical references
These references support the measurement and planning method. Product instructions, the site and applicable local requirements control the final installation.