Resealing Caravan

[RobKnapp2]

Hi All,
After resealing both the main rail, a window and the window rail on the offside of the caravan yesterday, ive had a good look around the other sealable joins etc. Most seem ok, however, I have a rooflight in the centre of the van (both side to side and front to back) that the sealant is visibly starting to come away.
It does look like the proper mastic has been used before, but I suspect that it is just old and has gone hard and chalky.
My question is, its too far to reach from a ladder safely from the side to remove the rooflight and then to clean up properly, so what is my best way of doing this?
It doesnt appear to be letting in water - the roof board is still hard and there is no staining etc, but im fairly certain that if I loosen the screws, then it will start to leak, so really need the faciliteis to reseal.
Its a 400x400 MPK type vent, and it does look a little worse for wear so I may opt to replace with a clear one.
For info, its a 1990 Swift Challenger 490/5se
Has anyone else done this, and am I looking at hiring 2 platforms or the like to access this area?
Thanks
Rob

 

[seth1]

Ive just replaced my rooflight complete after the blind broke and it was easier to get a mini heki.(2009 van)Very,very easy job.Start to finish took maybe an hour.At one point i thought it was going to rain.I worked from the inside out,with just a little set of steps.They seem to be held in with practically nothing besides the mastic.There is of course some self tapers but nothing major,the Heki fits in like a sandwich with distance pieces that are cut down to suit the depth of the roof,i think mine was 45mm from memory.The biggest job is moving the mastic to break the joint,it does try to lift the outer skin of the roof.I used a stanley blade on its own in one corner to lift it and just followed it round.Doddle.

 

[audiorob]

As with any of the jobs where re- sealing is involved cleaning off the old mastic is vital - the new won't seal with the old - then use a non-setting mastic or strip to ensure a new complete seal. I have a tiny plastic 'trowel' from an artist's shop, presumably intended for daubing acrylic paint to canvas, that is an idea size for seperating the old and trimming the new - easier to use than the stanley blade decribed on the other post!

 

[audiorob]

In fact the whole job is described with photos on the site - Advice - Elddis Projest - Replacing a leaking rooflight.

 

[Parksy]

When I fitted a Mini Heki replacement rooflight to a previous caravan I used a plastic fridge/ freezer scraper to remove most of the old mastic and then I cleaned the area with white spirit followed by meths to remove the greasy white spirit residue.
I did the job from the inside in the same way described earlier by Seth, easy peasy.

 

[colin-yorkshire1]

hi Rob, I have not had to change the roof light on the van yet but did replace one "and fit a extra one on the motor home, as it has been said very easy job if you do it systematicaly virtualy all the removing and fitting is done from the inside, save cracking off the old rooflight even cleaning the old sealer off can be done on a stool from the inside,
two tips I would give you though, it is better and a dam site easier to fit a new one of the right size than try to refurbish a old one as the outer plastic will be degraded if it has any age,and old ones seem to fall to pieces without any provocation while re fitting,
and after thoughly cleaning off the old sealer either use the mastic strips (easier to use) or before sealing with non set mastic like stick a flex draw around the profile of the roof light with a fine marker on the outside and mask off the edge with wide masking tape, thus when the fittings are tight any exess is easily removed when the tape is pulled off.

 

[RobKnapp2]

Thanks for all the replies folks. I replaced the rooflight in the bathroom a while ago (slight incident with wind

) and replaced this with a like for like. Its surprising, even a opaque dome, how much extra light is let in!
I agree that its not worth messing about with refurbing the old unit. From memory the replacement was approximately £40, and seems silly not to. My main concern was reaching the top so that I can properly clean up the area and reseal correctly, however, ill take the dome off at some point, that way I wont break the existing seal, and see how much access there is. Again from memory, the unit fits together like a sandwich from the inside and out, so, as suggested, the best bet is probably the sealant on a roll, and then I can slide it along the roof until I can reach it.
I presume that it would be a good idea to put some boards down inside the van to spread the load of me on the stool, and obviously a work sheet of some kind to save the carpet?!
Thanks again for the replies, and apologies for the delay in replying myself - work has been very hectic!
Rob