When a coating or restoration makes sense
A coating is usually a good option when:
- The membrane or metal is intact, with no large tears, open seams or failed panels
- The deck is dry and structurally sound
- The insulation is dry, or can be dried or replaced where it is wet
- The drainage works, or can be improved with tapered insulation or better drains
- The roof is weathered and showing age, but not failing in many places at once
- The building is occupied, and a tear-off would disrupt tenants or operations
A restored roof that is still sound can often last years longer than the owner expects, especially with regular maintenance.
When a coating is the wrong answer
A coating can't fix a roof that has already failed underneath, and we tell you when restoration is not the right choice. The usual reasons to skip it are:
- Wet insulation. A coating over wet insulation traps water in the roof system. It doesn't stop the leak.
- Deck damage. Soft or rotted decking has to be repaired before any coating, which can change the scope and cost.
- Too many layers. Most systems have limits on how many layers can stay in place, and a coating does not add a layer's worth of performance.
- Widespread membrane failure. Splits, open seams and blistering across large areas usually mean the system has reached the end of its life.
- Poor drainage. A coating on a roof that holds water in the same spots will wear out in those spots first.
What the roof needs before a coating
Preparation is what makes a coating last. Before any coating goes on, the roof needs:
1. A full inspection of the membrane or metal, the seams, the flashings, and the drains. 2. Repair of failed areas. Replace damaged flashings, repair splits and secure loose fasteners. 3. Drainage correction where water ponds, using tapered insulation or additional drains where needed. 4. Cleaning. The surface must be clean and dry for the coating to bond. 5. An adhesion test on a small section, where the coating system calls for it.
Skipping preparation is the most common reason a coating fails early.
Coatings on metal and single-ply roofs
Restoration is common on metal roofs, where a coating can address weathering and corrosion on sound panels, and on flat single-ply roofs in good structural condition. Mosaic is an ASTEC Authorized Contractor, and we install ASTEC roof coatings on commercial metal, flat and single-ply roofs. The right coating depends on the surface, the roof's condition, and the warranty the owner wants. We will tell you which coating fits your roof and what the warranty covers before any work starts.
How to decide
Ask a contractor to answer these questions in writing:
- Is the deck dry, and how do you know?
- What insulation is in the roof, and is any of it wet?
- What preparation is included in the price?
- What is the expected service life of the coating on this roof, and what maintenance keeps it that way?
- What warranty comes with the coating, and what does it require?
- How does the cost compare with a replacement over the next 10 to 15 years?
Next steps
If you have a commercial roof that looks worn but may still be sound, call (404) 260-3168 or request a condition assessment below. We inspect the deck, insulation, seams and drainage, then tell you in writing whether a coating makes sense, what preparation it needs, and what it costs compared with replacement.
For a roof that is already leaking, see our emergency commercial roof repair page. For help choosing between restoration and replacement, read how to make that decision.