03/25/2026
People asked me when should my Adobe Block house be sealed. Here is our answer:
Testing your adobe to see if it needs to be sealed (or resealed) involves a simple water absorption test to determine if the adobe is still water-repellent. If water immediately soaks into the wall, it needs to be sealed; if it beads up, the sealer is likely still effective.
The Water Absorption Test
Select Test Areas: Choose a spot on each side of the house, especially the sun-exposed south and west sides, which degrade fastest, and the shaded, moisture-prone north side.
Apply Water: Throw a cup of water, use a spray bottle, or splash water from a pan onto the wall.
Observe Results:
No Sealer Needed: The water beads up and runs down the wall, similar to "water on a duck's back". The adobe does not darken.
Sealer Needed: The water immediately absorbs and the adobe turns a visibly darker color.
When to Seal
The 5-Year Rule: As a general rule of thumb, you should perform a water test or re-coat your adobe with a quality water repellent every 5 years.
Failed Water Test: If the water absorbs immediately on any side of the home, it is time for a new coat of sealer.
Visible Deterioration: If you see sand or mortar "sloughing off" or turning into sand at the base of the wall, the sealant has failed.
Important Considerations
Do Not Use Plastic-Based Paint: Never use elastomeric paint on adobe, as it can trap moisture, causing the paint to bubble and peel away, potentially damaging the brick. Use a breathable water repellent instead.
Check Existing Sealant: If you have an existing sealant that is turning white or flaking off, the wall needs to be cleaned and resealed.
Stabilized vs. Unstabilized: Fully stabilized adobe does not strictly need to be sealed, but most older adobe homes are not fully stabilized and require a penetrating, breathable sealant.
Thank you,
Brian Flahive
Adobe Guys Tucson
VP Sales & Marketing
Office / Text / 520-492-1426
Email: [email protected]
ROC # 357673
