Chimney waterproofing products are available at home improvement stores, and some homeowners choose to apply them themselves. Here's an honest look at when DIY makes sense and when professional application is worth the investment.
If your chimney is in good condition — no cracks, no spalling, no deteriorated mortar — and you're comfortable working on a ladder or roof, applying a waterproofing sealant is a manageable DIY project. Products like Thompson's WaterSeal are widely available and easy to apply.
The key is preparation: the chimney surface must be clean and dry before application. Applying sealant over dirt, efflorescence, or damp masonry reduces its effectiveness significantly.
The most significant limitation of DIY waterproofing is that it's easy to miss the signs of existing damage that should be repaired before waterproofing. Applying sealant over cracked mortar joints or spalling bricks — which should be repaired first traps moisture inside the masonry — making the problem worse, not better.
Consumer-grade waterproofing products also typically don't penetrate as deeply as professional-grade products and don't carry the same warranties. ChimneySaver, the professional standard, carries a 10-year warranty when professionally applied — most consumer products offer no such guarantee.
Professional waterproofing makes the most sense when:
At Horizon, waterproofing is typically done as part of a broader service — after inspection, any necessary repairs, and cleaning. This ensures the sealant is applied to a properly prepared surface and that no existing damage is masked by the treatment.
Horizon Chimney Sweep serves Vancouver, Woodland, and all of Southwest Washington. Licensed, locally owned, and honest about what you need.