Frequently Asked Questions
The questions people ask after they find the stain.
Finding the Leak
The stain is in the middle of the ceiling. Does that mean the roof field is leaking?
Almost never. Water enters at a penetration or a seam, runs along the underside of a roof rafter until it finds a low point or a screw, and drips there. The field of the roof is one continuous membrane from the factory and is rarely the source. Look at the nearest vent, fan, AC, or cap seam first.
What is the right way to water-test?
Bottom up, one zone at a time, garden hose at moderate pressure, two to three minutes per zone, with a second person inside watching. Skirt and lower sidewall, then windows, then upper sidewall and corner trim, then roof edge, then roof field, then each penetration individually. Wait a few minutes between zones — the travel path can be long.
How do I tell how bad the damage already is?
A pin-type moisture meter run in a grid across the interior wall and ceiling panels. Compare readings against a known-dry area of the same unit. Then press on the panels — any softness or flex means the substrate behind it is compromised, regardless of what the meter says.
It only leaks when it rains hard or when I am driving. Why?
Wind-driven rain and highway airflow push water uphill and sideways in ways a vertical hose test will not reproduce. Cap seams, corner trim, and window flanges are the usual culprits for a leak that only appears at speed. Test those zones with the hose angled up under the trim rather than straight down.
Repair vs. Rebuild
Can I just coat over the wet spot and stop it?
No. Sealing the exterior over saturated framing traps the moisture inside the laminate, where rot continues without oxygen exchange or drying. The wall has to be dry before anything goes over it. If it is currently wet, that gets addressed first — either opened up or dried with weeks of dehumidification and airflow.
How do I know if the camper is worth fixing?
Push on the walls and ceiling around the stain. Firm panels and a dry meter reading mean you are in the cheap repair window — seal it and the problem stops. Soft spots, bubbling in the exterior skin, or waves in the sidewall mean delamination, and that is a reconstruction job that frequently costs more than an older unit is worth.
What if I already re-caulked it and it came back?
That is the normal outcome. New sealant bonds to old sealant rather than to the flange, so when the original bead lets go underneath, water gets a sealed channel to travel sideways. The fix is to remove the sealant entirely and replace the joint with a continuous membrane rather than a better bead.
Do I have to strip the whole roof, or just fix the one spot?
Technically you can spot-treat. Practically, if one flange sealant has failed at five years, the others are the same age and the same product. Most owners who spot-fix are back the following season on a different penetration. Sealing the full deck and every detail at once is usually the better economics.
The Membrane Itself
How long does the polyurea membrane last?
There is no sealant joint left to age out, which is what sets the clock on a factory roof. The membrane itself will chalk cosmetically under UV over many years but retains its physical properties. The realistic maintenance item becomes physical damage — a branch strike or a new hole drilled for an accessory — not scheduled resealing.
Will it stick to my old EPDM roof?
Yes, with the right prep. EPDM sheds a chalky plasticizer layer as it ages that must be removed with Super Orange Cleaner — two passes on a neglected roof — followed by 7001 Primer. Skipping either step is the single most common cause of coating failure on rubber roofs.
Can I spray it myself?
Alasta Seal requires a plural-component proportioner with a heated hose, Graco Reactor E-20/E-30 class or equivalent. It is not a roll-on or airless product. If you do not have a rig, we can refer you to an applicator or discuss what adding the capability involves.
How much material will my roof take?
One gallon yields 1,604 mil-sq-ft at 100% solids — roughly 32 sq ft at a 50-mil spec. A 24-ft towable with about 200 sq ft of deck runs 7–8 gallons for the field plus extra for the 80-mil detail build at flanges and seams. Send us the length and roof type and we will do the math for you.
Question We Did Not Cover?
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