Where the hell is this water coming from!!!????

[Colinn]

Hi, can anyone advise with this one....???

Quite out of the blue, the rear roof vent of my four year old van developed a small but annoying drip of water when it rained. I re-sealed the existing sealant around the roof frame with Dow Corling waterproof sealant = but still the annoying drip from one corner persists. I tightened the existing screws in the unit in case there was a problem/crack there, but no solution.

The drip does not seem to come from any seal between the roof and the unit - more from the unit itself. It is the type where the vent closes down over the frame... Regrettably, there always seems to be a pooling of water on the roof in this area (bad design fault). Thankfully, the ingress doesn't seem to be affecting a wider roof area...

I suppose the only answer is to get a dealer to refit - but wonder if there's a simpler solution. Anyone else come across this problem??

Tks.

 

[Damian]

Colinn, unless you have properly prepared the arae for sealing, then you have wasted your time.

If the water is getting through the original seal, then the only way to effectively deal with it is to remove the vent, completely remove the old sealer, clean and prepare the roof of the van and frame, then use new mastic.

Dow Corning is NOT recommended as it sets as it seals, but any movement breaks the seal , leaving you with the same problem, and in varying temperatures, there is movement of the roof.

 

[Barkas]

Hi Colinn. Running a bead of sealant around an existing seal rarely works, I find that the old mastic refuses to bond with the new as the oils have leeched out over time and the old mastic has become dry were it is visible which is what causes a lot of the black streaks you find on caravans, and if it does work it wont last for long, wait for a good forecast and take the old vent out of its frame, tease it out gently whilst breaking the seal with a plastic spatula or similar tool to avoid scratching the roof panel, clean off mastic and reseal with a caravan mastic, its not a big job and you should be done and dusted in 1 hour. 2 tips....1st, if your van is more than 10 years old you will find that a decade or more of sun will have taken its toll on the plastic vent and it may easily crack as you tease it away which leads to my 2nd tip....make sure that there is a dealer open on the day you remove it so you can pop along and get a new one if it does break.

 

[JTQ]

As a method of determining if the leak is the seal to the roof or elsewhere you could try covering that "flange" with Duck tape.

I am not suggesting for a moment this as a solution as its very much a bodge but I did this with a car sunroof once to see if it was the source of a wet footwell. [ It was a door seal so saved an expensive miss diagnosis]

 

[TonyH1]

Hi Colinn, you don't say what make of caravan you've got. Some have a 5 year warranty, have you checked yours?

 

[Colinn]

Thanks for suggestions, I am monitoring and will perhaps get it sorted at service. (Tony - van is out of warranty).

Tks.