Mastic Sealing

by simontm1959 Sun 3 Apr 2022 - 17:52

I can't find any posts about this, but has anyone got a solution for mouldy mastic.

The Broadway is only 3 years old and it's really spoiling the look of the van - i've attached a picture of the affected roof mastic, but the side wall mastic is similarly affected.

Thanks

Simon

PS - Does anybody know where i can get cable ties with the sticky pad for the aerial cable - they've all come off![You must be registered and logged in to see this link.]

by Caraman Sun 3 Apr 2022 - 18:59

Regular roof cleaning helps as does parking the van on a slope so rain water doesn't pool on the roof. I park mine with the rear nearside wheel on a levelling wedge which seems to do the trick. As for cleaning that horrible black stuff, I have found the best way is with a small quantity of neat thick bleach scrubbed on with an old toothbrush and then left for a while to do its stuff before rinsing with fresh water. It doesn't get it all off and it sometimes leaves a slightly pink hue behind but its an improvement. If you are going to do this, take care to keep the bleach away your clothes and skin.

by Roopert Sun 3 Apr 2022 - 19:05

Regarding the cable tie bases - self adhesive bases are easy enough to buy, but I don't any more for exposed locations, because the standard ones are no good for paces that get hot in the sun.

If you still have the bases without the "sticky", clean up the underside and cut your own sticky pads out of 3M VHB double-sided tape or equivalent.

by gpilky Mon 4 Apr 2022 - 9:17

Looks a bit like mine!!!

I used Slinky last year and it helped. Apply using an old toothbrush. Wasn't perfect though and I expect it might take a few goes.

This time I will try applying it with a polishing pad on my Dremel and see if it works better.

by Eltel Mon 4 Apr 2022 - 9:45

I have the same problem with the seal between the top of the windscreen and motorhome body.

The dealer has told me there cure on vans for sale is to remove the old sealant and replace.

The previous post mention ‘Slinky’ not sure what that is ?

I do however have a Dremel drill though

Thanks

Terry

by Caraman Mon 4 Apr 2022 - 10:00

I've just looked up removing mould from silicon sealant on Google and the suggestions in order of potency appear to be ammonia, bleach or baking soda & vinegar paste. I've not tried the first and third methods but might in the future. It seems the secret is to kill the mould by penetrating its roots. I'm not sure that normal surface cleaners will do that.

by Eltel Mon 4 Apr 2022 - 10:09

Many thanks Caraman

My only concern would be in using any of the above is that could it penetrate the seal and let in water.

Terry

by Caraman Mon 4 Apr 2022 - 10:19

I've used the bleach method in the bathroom with no ill effect and so far no ill effect on the motorhome. If that is a concern I am pretty sure a vinegar baking soda paste would be fine.

by Roymck Mon 4 Apr 2022 - 11:48

Soak some cotton wool in bleach and leave on the mouldy area for a few hours then neutralise with water , also works a treat at home on the grouting round the bath and in the shower .

by fred1 Mon 4 Apr 2022 - 13:01

Try fungicidal spay it kills and removes mould and mildew and prevents against regrowth.

by sunidorset Mon 4 Apr 2022 - 14:15

Our "60" reg Broadway's sealant was pretty sad all round so I replaced most of the mastic with Sikaflex 512 - it should last a while. (My Dremel wasn't allowed out of the drawer!)
Has anyone used "Mould Magic" by " Must Have Ideas"?

This week's project with the downturn in the weather has been removing rust from the (steel) spare wheel with Jenolite and then priming and painting.

by Pete F Mon 4 Apr 2022 - 15:52

I use Elbow Grease, degreaser which comes in a spray bottle for around £1. Spray on neat, leave for a short while then scrub off and for this I use a Sonic Scrubber, (like an oversize electric toothbrush, last seen in Lakeland for about £15). It can get some dirt off but if the mastic itself is discoloured then I haven’t found anything that works and being a panel seal I am loathe to disturb it, particularly knowing that any replacement will do the same.

by gpilky Mon 4 Apr 2022 - 15:57

Sorry - I meany Silky snigger

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by Chris_U Mon 4 Apr 2022 - 22:59

simontm1959 wrote:I can't find any posts about this, but has anyone got a solution for mouldy mastic.

The Broadway is only 3 years old and it's really spoiling the look of the van - i've attached a picture of the affected roof mastic, but the side wall mastic is similarly affected.

Thanks

Simon

Yes, try Cillit Bang Black Mould remover. It works well in my shower both on the grouting and the mastic sealer, but my motorhome has not needed it so far.

by simontm1959 Tue 5 Apr 2022 - 10:41

Thanks for all the replies - I think I'll start with the Cillit Bang and if that doesn't work onto bleach!

by Guest Tue 5 Apr 2022 - 11:46

I wouldn't bother with Silky. All you'll get is sore arms and not a noticeable difference in bodywork appearance. Definitely doesn't remove mould.
I once watched a video comparing a Hymer motorhome to a Swift. Where the Swift had exposed sealant on all the seams the Hymer had aluminium strips with rubber seals. Definitely looked a far better method. Even the vertical exposed sealant seams get mouldy. It's just the design of most affordable motorhomes and being exposed to the elements. I've often wondered if a similar motorhome that was always located in a drier climate would develop mould.

by sidecutter Tue 5 Apr 2022 - 17:04

Hi, Simon we had the same problem with our Broadway EL we tried in vain to remove it, it was all around the cab area what removed it was Cillit bang black mould remover it took a few applications but it worked,hope this helps.

by simontm1959 Tue 5 Apr 2022 - 18:17

Cillit has worked a treat - just as well as I didn't have my best cardie on though as it is quite brutal on clothes :)

by groundhog Tue 5 Apr 2022 - 18:50

There is only one way to get perfection and that is remove the old silicone and replace with a quality product. I have tried all sorts of quack remedies on yachts and our motorhome and frankly none of then work.....but
SWMBO suggested trying cilit bang black mould remover, I was extremely sceptical but best keep her happy. Now the results are not perfect by a long shot but it is by far the best thing I have tried and gives a vast improvement. Spray it on, leave it for a bit then I wash it off with loads of water.
Worth a crack!

by mrsolo Wed 6 Apr 2022 - 21:29

All the mastic seams on our 11 plate Broadway EL look pretty grim, I am relucktant to remove & replace them as we have no water leaks at all @ pres. Sods law may prevail if I remove & replace them, I could wind up with a leak/leaks!!!

I am experimenting by cieaning the mouldy seams & painting them using a thin artist brush & gloss paint matching the body work, slowish job but looks good.

by RalphHughes Thu 7 Apr 2022 - 13:27

I use Astonish Mould & Mildew remover, works a treat, available from Amazon
As simontm1959 says, it will wreck any clothing it gets on, ruined a brand new tee shirt this week using it confused3

by simontm1959 Fri 8 Apr 2022 - 9:29

So after just having a habitation check earlier this week, I decided to clean the mastic as discussed above, unfortunately found cracked mastic on the roof between the cab and habitation area - another warranty claim....... and another round trip to get it fixed grrrrrr

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by groundhog Fri 8 Apr 2022 - 9:40

Not singling out Autosleepers but pretty much all manufacturers use the cheapest products, if you compare what is used on quality yachts you will see the difference. Guess the trouble is everything is built to a price but if you can afford to spend £80K on a new van is there not an argument to say make it £85K and build it properly?

by simontm1959 Fri 8 Apr 2022 - 9:43

Amazingly, the company who did the habitation check (on Monday) says 'think the seal might have split after the check' hahaha - I am not sure how to answer this!

by groundhog Fri 8 Apr 2022 - 9:55

In the same way Russia is carrying out a "special operation".... confused3

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