What the service should establish
Ask which material is being treated, why the product is compatible, and what preparation is necessary. A coating does not repair failed flashing, missing mortar or a broken crown simply because all can contribute to water intrusion.
Where the scope stops
Request product information, application limits and exclusions. The contractor should distinguish reducing absorption through suitable masonry from guaranteeing that the entire chimney can never leak. Keep the diagnosis separate from the sales description of the product.
The Advisor standard · Define before deciding
Distinguish absorption control from defect repair
A water-repellent treatment may be proposed for suitable masonry, but the contractor should first identify the material and explain the intended purpose. Ask which defects have been assessed and which repairs must precede application. Treating a surface and correcting a failed junction are different purchases.
What a comparable proposal looks like
Request product information and the proposed preparation. Ask about existing coatings, application conditions, maintenance and the scope of the warranty. A promise to stop every possible chimney leak is broader than a proposal to reduce moisture absorption through a specified surface.
Four items to take away
- Material and existing coating assessment
- Product and preparation
- Prerequisite repairs
- Treatment limits and warranty
Should waterproofing come before leak diagnosis?
Ask for the evidence first. A product may be useful in an appropriate plan, but purchasing it does not establish where water entered or whether damaged components need repair.
Original homeowner comparison checklist, not a technical specification. For maintenance and inspection background, see CSIA homeowner resources. Follow the applicable appliance instructions and on-site findings. How this guidance is produced.
Background and safety references
For inspection and maintenance background, consult CSIA homeowner resources. Product-specific work follows the applicable manufacturer instructions and local requirements. Our official resources page separates government safety advice from industry education.