Fitting the rooflights, be very aware!

Millie Master

Forum Member
When I built 'Millie' I was very aware of all of the dangers and associated pitfalls of fitting rooflights to panel van roofs that have strengthening ridges in them.

I spent ages searching around various scrap piles at my local UPVC double glazing installation companies before finding sections of off cut trim pieces that were exactly the same thickness as the depth of the valleys in the roof, I then methodically cut them so that they were exact fits, I then very thoroughly degreased and squeaky cleaned both the inside and outside of the roof where the tanalised strengthening ribs were going to be stuck to the inside and more importantly where I was going to be bedding the plastic trim pieces onto the outside of the roof using black Stixall which I quite literally flooded in before then very carefully mounting/fitting the MPK rooflight of my shower room. Perfect, well pleased with the result.

Roll on 5 high mileage years and hundreds of night stops later, when over in the Lincolnshire Wolds on Wednesday, continuous drips of a mucky brown watery liquid started to drip down, even when it wasn't raining outside. So yesterday we returned home a couple of days early and I immediately set to work removing the offending rooflight only to find all 4 pieces of the 25 x 50 tanalised timbers I had used and quite an area of the Morland vinyl faced ply was now sodden and rotten :mad:

So I have now fully stripped back and cleaned up both the inside and outside and in doing so I was scrupulously checking for any signs for where the bloody water had found its' way in, which, to be honest, if there were any points of entry, they were so finitely small that to the human eye, they were not visible!

Today, I will continue to clean up the entire area both inside and outside, treating the rust that has penetrated from the cut lines in the roof that I had painted after cutting, I will then be be re-painting with a few coats, before then refitting the roof on new plastic trim pieces and fresh kiln dried timbers and cutting and fitting a new entire ceiling to the shower/loo room............ What a pain it has been and all because of a couple or so minute pin prick holes through which water had seeped.

This time though, I will also be putting in a nice thick bead of Stixall around the entire van roof to rooflight joint when I have finished, after all the roof of a van isn't looked at all that closely very often is it. I will also be cleaning the entire areas around the other two installations and running a very thick bead of Stixall around them as well, just in case. Once bitten twice shy :mad::mad::mad:
 

SquirrellCook

Forum Member
This is why I try to avoid normal timber and ply at all costs. I've reinforced Betty with Buffalo Board. I have a piece I've been using for a few years in the garden as a kneeling board for weeding. Not a trace of rotting.

 

Millie Master

Forum Member
Use carafax or similar instead of stixall. It is a bedding compound rather than an adhesive.

But Chris, as an ex caravanner of the old flimsy type of construction for 30 + years, one of the pet hates of everyone I knew as well as myself was anything like a mastic, which surely Carafax is ?? The reason being that in time it dries out and then cracks, allowing moisture in.

In my former years over on SBMCC and then on DIY the vast majority of people were either using Sikaflex or Stixall as they not only bond exceptionally well, but they also remain slightly flexible.

However Chris, as you have suggested using Carafax and although not having any of that, I do have some very high quality mastic, so I am going to bead bond the plastic spacer strips on with Stixall to the outer edges and then a wide beed of mastic to the inner edges, following which I will then butty knife a whole lot more mastic all along the edges so as to hopefully ensure a belt and braces bonded joint.

As for the timber, well I had considered using several thicknesses of marine ply when doing the original build but ended up using 25 x 50 roofing laths, which, like an idiot I thought might have been more rot resistant, how wrong I was!
But this time, simply because I have the laths already and they are bone dry I am using them again and the ceiling is going to be 3.6 mm exterior ply which I will be painting both sides, the reason being that I don't have any vinyl faced Morland ply which is a bit of a bugger!

Oh well onwards and upwards

Phil
 

wildebus

Forum Member
Interesting.
I have seen that the most popular way to fit roof fans and Venta is to make up a ply frame for the underneath, but I decided when I fitted my Maxxair Fan was to just screw into the metal to secure it to avoid possibility of wet wood.
Seemed to have worked out fine (I did of course cover all screws outside with sikaflex or whatever to seal them right as well as the area where the frame joins the roof)
Also used beutal (putty) tape sandwiched between roof and frame support and I think that is a very key component to stop water ingress.
 

wildebus

Forum Member
This is why I try to avoid normal timber and ply at all costs. I've reinforced Betty with Buffalo Board. I have a piece I've been using for a few years in the garden as a kneeling board for weeding. Not a trace of rotting.

I can't recall the name of the product but there is a boarding sheet material that is used in wetroom - you use it on the wall where you would typically use plaster board. From memory it has similar properties to wood except it is totally waterproof. I wonder if that is the same as buffalo board? (Expect this stuff I am thinking of is definitely not wood)

Not used it in a vehicle but used it when redoing my bathroom in last house.
 

Nabsim

Forum Member
I had to replace the roof light over the bed last year, couldn’t source an original so used a mini heki that was the same size as the opening. It left a problem the original was moulded to fit in circular cutouts on each corner and centre of each edge. The plastic frame of the roof light covered these so thought it would be okay. I used a white butyl mastic as recommended to me at O’Leary motorhomes and all was good until mid Feb.
I waited for rain to stop then had a look. I couldn’t see where anything could get in so I went around the edges with more butyl. I had removed the inner cover to allow it to dry out and ordered some low expansion foam. Once nicely dried I filled the curcle cut out with the expanding foam thinking that would be the end of it.
All good til we started getting some real heavy downpours towards the end of June when it sometimes dripped again. There was one edge I couldn’t get to but didn’t think it was coming from there as I had been looking with inner cover removed during storms. More bad storms forecast for a couple of weeks and maybe a month before I could get the van near son in law who can get on the roof.
After a fair bit of reading up I ordered a time of Polar Leakseal clear and painted a couple of inches around the 3 sides I could reach. So far it’s job done, we have been in a god number of very heavy and prolonged storms and not a drip. If anyone suspects a pinhole leak I would recommend this stuff so far, it stays flexible for years.
 

Nabsim

Forum Member
I have some of the following which is a recommended product from lots of people on the VW Forum.
I have not actually used it but I had to buy it just because of the name! (click to see ;) )

I have some of that but because I couldn’t see where it may be getting in I didn’t think it would work in this instance. I wanted something I could see would coat from the plastic cover to a couple inch around to make sure. I suppose I could have doused it all over and it may have found the fault okay. I needed something that would withstand rain immediately after application though as I coated between showers.
 

SquirrellCook

Forum Member
I never really trust any product with a funky name. If it was any good it be in use in industry.
Remember when bigger money is involved the products have to work or you could find yourself in court.
 

wildebus

Forum Member
I never really trust any product with a funky name. If it was any good it be in use in industry.
Remember when bigger money is involved the products have to work or you could find yourself in court.
it is actually a well respected and established product. And the name - while also amusing - describes very well what it is for.
 

Millie Master

Forum Member
I have some of the following which is a recommended product from lots of people on the VW Forum.
I have not actually used it but I had to buy it just because of the name! (click to see ;) )


Do you have any idea how it is supposed to be applied David, brush or simply squirt?

Phil

ps.

My roof is now back together and if any water gets through what I have just done then I will be amazed!! But I am now thinking of my other rooflights and mushroom vent.
 

Deleted member 4404

But Chris, as an ex caravanner of the old flimsy type of construction for 30 + years, one of the pet hates of everyone I knew as well as myself was anything like a mastic, which surely Carafax is ?? The reason being that in time it dries out and then cracks, allowing moisture in.

In my former years over on SBMCC and then on DIY the vast majority of people were either using Sikaflex or Stixall as they not only bond exceptionally well, but they also remain slightly flexible.

However Chris, as you have suggested using Carafax and although not having any of that, I do have some very high quality mastic, so I am going to bead bond the plastic spacer strips on with Stixall to the outer edges and then a wide beed of mastic to the inner edges, following which I will then butty knife a whole lot more mastic all along the edges so as to hopefully ensure a belt and braces bonded joint.

As for the timber, well I had considered using several thicknesses of marine ply when doing the original build but ended up using 25 x 50 roofing laths, which, like an idiot I thought might have been more rot resistant, how wrong I was!
But this time, simply because I have the laths already and they are bone dry I am using them again and the ceiling is going to be 3.6 mm exterior ply which I will be painting both sides, the reason being that I don't have any vinyl faced Morland ply which is a bit of a bugger!

Oh well onwards and upwards

Phil
Think we are talking about different products Phil, this one doesn't 'set'.

LINK
 

wildebus

Forum Member
Do you have any idea how it is supposed to be applied David, brush or simply squirt?

Phil

ps.

My roof is now back together and if any water gets through what I have just done then I will be amazed!! But I am now thinking of my other rooflights and mushroom vent.
I thinking you squeeze it into the area where you suspect the water is getting in and it makes its way down the pathway to seal it. If you are interested in this product I will check the info on the back of my bottle.
 

wildebus

Forum Member
For What It's Worth, this is the end result of my Fan Installation

Finished outside
by David, on Flickr
Not the prettiest finish but effective.
The rib and raised circular bit are just ahead of the frame. I was lucky that I managed to select an area on the roof for which I didn't have to deal with adding filler pieces

Inside, as mentioned, I didn't bother with a wooden frame.

Fan Fitted - Waiting Garnish
by David, on Flickr
I know having a frame is much more typical but I found not having one seemed to work just fine.
 

Millie Master

Forum Member
Think we are talking about different products Phil, this one doesn't 'set'.

LINK

Chris, I found some kind of high quality mastic product in my locker this afternoon and it was still in perfect condition, so I have done as I wrote earlier and have used a combination of both Stixall and this mastic goo.

Sorry to say that it took me all bloody day to do what I used to do in 10 mins. today and so, as it had to be done I have now reached a stage where I can safely pack my tools away for a day or so until I have enough energy to finish off the job.

many thanks

Phil
 

Bouydog

Forum Member
it is actually a well respected and established product. And the name - while also amusing - describes very well what it is for.
I have used that on my bonded car windscreen that developed a leak along the top joint. Two applications just dribbling it into the joint no more leaking that was around six months ago.
 

Nabsim

Forum Member
Do you have any idea how it is supposed to be applied David, brush or simply squirt?

Phil

ps.

My roof is now back together and if any water gets through what I have just done then I will be amazed!! But I am now thinking of my other rooflights and mushroom vent.
If you want to put some leakseal round I still have an almost full an and currently in Hull
 

Squiffy

Forum Member
Do you have any idea how it is supposed to be applied David, brush or simply squirt?

Phil

ps.

My roof is now back together and if any water gets through what I have just done then I will be amazed!! But I am now thinking of my other rooflights and mushroom vent.
I had leak in my yacht side window years ago, and I bought some of captn Tollys, your meant to drip it on where the leak is and it self seeks and seals the leak, it was totally useless in my case as after several tries it didn't stop a drop getting in, in the end I had to remove the window and put a new sealing gasket in, one hell of a job thats why I tried captn Tollys first as recommended by the local boat chandlers, it was only one small drip so the leak was very small but every time we went out and the sea was slightly rough any water running along the cabin windows on a Lee side and when we arrived where we were going the seat had an annoying damp patch. They were the days though I sometimes miss them badly but have to say it's a lot easier driving to a destination 😁. Phil
 

Users who viewed this discussion (Total:0)

Top