...Water leaks..

[afandy]

...Hi have been away last weekend and that bad weather did take its toll...

..I have 2 water leaks from the roof /window...is there special clear sealants for campers or can i use household sealants....Andy

[Brian Kirby]

Andy

You really need to tell us a bit more.  Roof window?  Is this a rooflight, i.e. installed in the roof of a high top panel van or a coachbuilt, or is it a window in the side of a high top conversion, or in the luton of a coachbuilt.

Generally, you should remove the window, clean it and the surrounding bodywork of all old sealant: dry thoroughly, and then reinstall, re-bedding on new sealant.   However, do check the opening thoroughly for signs of decay or rot, since it is probable this leak has been ongoing for some time, just at a lower rate so you hadn't noticed it before.

What sealant will work best will depend on what things are made of, for example silicone doesn't adhere well to certain plastics.  In other respects silicone would be an excellent choice, but don't use the bath seal variety.  Use an exterior grade coloured as closely as possible to match your van, not clear.  Buy from a builder's merchant or a good DIY store with a wide range. 

Apply liberally, install the window and tighten it lightly down, so that a bedding of about 2mm of sealant remains between the window frame and the van bodywork.  Don't over-tighten, the sealant bedding is essential for it to work.  Clean up all around and leave for 24 hours to set.  Then, gently tighten the frame a bit more, to just compress the silicone bed and ensure it is held under compression.  The bedding will then act like a made to measure gasket, and you won't be wholly dependent upon its adhesion for a seal.

Good luck.

[Vernon B]

afandy - 2007-05-31 10:01 AM

 

...Hi have been away last weekend and that bad weather did take its toll...

..I have 2 water leaks from the roof /window...is there special clear sealants for campers or can i use household sealants....Andy

 

Hi Andy

 

Just a thought. I bought my 'van four years ago (a 2003 model) and it had a Heki roof light fitted as standard. It happened to be a new version of its type and the manufacturer's underestimated the expansion that would take place when the unit was exposed to direct sunlight. As a result many of them broke their seals (mine included!). I'm pretty sure there was a general recall and the dealers had to remove the units, open up the aperture and then refit them.

 

May be worth checking if your's was one of these (but not recalled) before you're tempted to follow Brian's excellent DIY advice

 

 

Vernon.

[Tanskavan]

Hi

 

I have a Bessacarr 760 with a heki roof which leaks in heavy rain when driving. The 2 other roof lights ahve a small strip of plastic accross the front edge where the hinges are. I was wondering if there should be one at the front of the heki roof to deflect the rain. Any ideas?

 

Cheers

 

Tony

[Derek Uzzell]

Using silicone sealant to fix water leaks through motorhome windows must be considered a bodge. However, it can be a very effective bodge if the leak is minor and the window isn't on the roof where it lacks any protection against wet weather.

 

One of the side-windows on my Herald leaked slightly in very heavy rain and inspection of the interior wall-covering revealed that this must have been occurring from the time the motorhome left the factory. Rather than remove and re-seal the window (which would have been the 'professional' thing to do) I thoroughly cleaned the narrow gap between the window-surround and the bodywork, carefully masked each side of the gap, then squirted clear silicone sealant into the gap smoothing off with the DIY-er's wet finger. This fix proved to be completely successful (and virtually invisible) and, when I checked the other windows, I noticed that the same treatment had (prior to my owning the Herald) been given to one of them.

 

If the window is to be removed and re-sealed then high-strength polyurethane sealants (like Sikaflex-512 Caravan or Sikaflex-252) would normally be employed to re-make the joint. ("Roof vent" forum thread beginning 30 May 2007 may also be useful on this subject.)

 

Tony:

 

Motorcaravan manufacturers (particularly UK ones) have habitually fitted SEITZ HEKI 2 roof-lights to their products. This practice began when there were only two HEKI models - the light, cheap "2" designed specifically for caravans and the heavy, expensive "1" intended for motorhomes. It's hardly surprising that budget/weight conscious motorhome builders opted for the former model over the latter, nor is it surprising that this choice has resulted in on-going complaints about wind-noise, draughts, rattles from blinds, etc. from owners of HEKI-2-equipped motorhomes.

 

I'm sure motorhome designers take little account of the effect of air-flow over their conceptions' roofs, so it's pot luck what impact this has on roof-lights when a motorcaravan is being driven. Your Bessacarr's aerodynamics are apparently causing rain to enter. SEITZ do market 'spoilers' to fit in front of their roof-lights (though only the "2" model is really likely to benefit) and these come in two lengths - 810mm or 1110mm - to match the orientation of the roof-light's rectangular shape. Both lengths of spoiler are available from Caravan Accessories (CAK) Ltd (advert in MMM) and the cost of each is around £30.

 

However, although I've heard/read plenty of complaints about the HEKI 2 problems I've mentioned above, I don't recall rain-ingress being highlighted before. So, before taking the Spoiler Route, it would be sensible to confirm first that your roof-light has the correct rubber seals, that these are in good condition and that the roof-light's top fits tightly against the seals when it is in the closed position. If those criteria are currently being met, then fitting a spoiler would be your best bet.

 

The HEKI 1 roof-light has fallen out of fashion (too heavy, too dear) and right-thinking motorcaravan manufacturers nowadays fit HEKI 3 or its electric HEKI 4 equivalent. However, that hasn't stopped the cheap-skates still tacking HEKI 2s on to their 'van roofs. Something to bear in mind when looking for a new motorhome.

[b6x]

Derek Uzzell - 2007-06-01 9:20 AMThe HEKI 1 roof-light has fallen out of fashion (too heavy, too dear) and right-thinking motorcaravan manufacturers nowadays fit HEKI 3 or its electric HEKI 4 equivalent. However, that hasn't stopped the cheap-skates still tacking HEKI 2s on to their 'van roofs. Something to bear in mind when looking for a new motorhome.

 

Is it easy to tell which is which? My van apparently has "Heki MIDI" roof vents - whatever they are.

 

b6x

 

[Brian Kirby]

Derek

I'm afraid I have to say I think your dismissal of the use of silicone sealants as a "bodge" is a bit too sweeping.  It's all about horses for courses, and the main reason I advocated a construction silicone is that they have long life, estimated at around 25 years (so presumably adequate for most motorhomes :-)), excellent elasticity, greater bonding capability to a number of plastics, and greater high temperature tolerance, than most other commonly available adhesive sealants.

For example, sticking (no pun intended) to Sika products, Sikasil's adhesion to plastics (mainly PVC), and its temperature tolerance are both, according to Sika's own data sheets, superior to 512 Caravan.  512 Caravan being primarily aimed at application to wood, metal and painted surfaces.  Other well reputed and formulated exterior quality silicone sealants (therefore excluding bath sealants), will broadly share these characteristics.

Because the item in question here is a "window", (type unspecified, but likely to include a plastics frame) I think a silicone based, rather than a polyeurethane based, sealant may give a better result. 

However, whichever is used, the best result will require dismantling, thorough cleaning, and re-assembly with new sealant.  The leakage may be checked by an edge fillet as you describe, but the underlying problem: an incomplete seal, won't have been addressed, and the joint will remain liable to further leakage in future.

The point I'm trying to make here is that a cure is preferable to a palliative, wherever this can be achieved.  My concern is the insidious nature of water ingress, with its ability to seep into panel type constructions without manifesting visibly, where it causes considerable unseen damage before making it's presence obvious.  I know what I'm advocating does seem rather radical but, for the extra effort involved, eliminating the leak, and with it the future risk of rotten timber framing, with all that implies for expense and heartache, seems to me worth taking.  As ever, however, yer pays yer money..........!

[Derek Uzzell]

b6x:

 

Descriptive information on HEKI roof-lights can be found on Dometic's website. See

 

http://www.dometic.com/templates/ProductCategory.aspx?id=674

 

Identifying one HEKI model from another is relatively straightforward if the aperture in the leisure-vehicle's roof is (roughly) measured. Mini-HEKI requires a 400mm x 400mm 'hole', Midi-HEKI a 700mm x 500mm cut-out, while the HEKI 1, 2, 3 and 4 models all need a 960mm x 655mm opening. HEKI 2 (and the sself gratificationier De Luxe variant) is aimed at caravan applications, whereas all the rest are designed to be suitable for motorhomes or caravans.

 

I've found it quite common for members of the UK motorhome trade to employ the term "HEKI roof-light" for any big roof-window irrespective of the manufacturer. This (like the use of the archaic term "zig unit" to mean any 12V control panel) can sometimes lead to confusion.

 

I once visited Brownhills at Newark to inspect a Hobby motorhome. Beside the LHD demonstration vehicle was a notice board detailing the UK specification that comprised RHD, a gas oven, wood dashboard finish, fire-retardant upholstery and a "HEKI roof-light". Brownhills' Hobby was fitted with a mid-size Remis REMI-TOP roof-light that I knew to be part of the standard specification, so I asked the salesman which HEKI model replaced the Remis unit for the UK market. He told me that no replacement took place - the HEKI roof-light fitted to their demonstrator was the one fitted to UK-spec Hobbys. While I could perhaps understand that a motorhome salesman might lack my train-spotter's eye and not be able to distinguish instantly between different makes/models of roof-lights at 50 paces, I've often wondered why it was felt necessary to tell UK potential buyers they would be getting something they couldn't avoid having.

 

Having said that, I vividly recall entering a Euro Mobil A-Class show-motorhome at the NEC and overhearing a couple who were leaving say "This one's useless - it's LHD and there's no oven". Yet immediately outside the motorhome's door was a very large notice prominently proclaiming that UK-specification models were RHD and fitted with an oven. Proves that sometimes you just can't win!

[Brambles]

Hi,

My roof window has 4 screws to mount the clear window on to the opening assembly.... took me ages to trace the leak to one of the screws and cup washers just needing tightened against the rubber mounting washers.

J.