Fixing an outside hatch frame

[Caroline]

Advice please

 

The under bed outside hatch frame is coming unscrewed from the van, I can see it has previously been fixed with silicone.

 

Is this normal outdoor silicone?

 

I would guess that the screw holes are now worn out as the screws come out, what can I do to fix this.

 

(?)

[Derek Uzzell]

It’s not easy to advise on this without seeing the vehicle (or at least a photo of the faulty hatch).

 

With sandwich-panel construction, where there’s an inner and outer skin with insulation sandwiched between, it would be common practice to have a wooden framework surrounding any aperture made in a body-panel to accept, say, an external hatch or window. The wood would be introduced between the two skins to provide extra strength and to allow screws to be used as fixings.

 

With an external hatch I’d expect the sealant used to waterproof the joint between the hatch’s frame and the body-panel to be something like SIKAFLEX-512, rather than silicone, though a good quality constructional silicone sealant would probably be OK.

 

It needs to be asked why the fixing screws are loose as, if the screws haven’t rusted (they should be stainless-steel), are the right size and there’s an adequate framework surrounding the hatch’s aperture, there’s no obvious reason for them to do this.

 

If the hatch-frame has become detached from the body-panel, it might be best to remove it completely to check what’s behind the frame and then reseal/re-screw it.

 

If it’s just the fixing screws that are loose, then I suggest you remove them, poke a thin screwdriver (or a piece of wire) into the screw-holes and, if it’s evident that there is a something behind the frame for screws to ‘grip’ on, you can either glue bits of wood into the screw-holes and re-drill them, or use a larger gauge of screw. In either case, some sealant should be put in the screw-holes before introducing the screws to prevent water entering via the holes.

 

[Caroline]

thanks

 

i would guess the problem has been caused by dragging items over the lip of the frame and perhaps pulling the frame away from the body.

 

*-)

[Guest peter]

Do not use silicone for this job, as it's a sealant and not meant for it. Take off the frame and remove ALL silicone and stick it back in place with Sikaflex 221 or other suitable adhesive / sealant.

[Caroline]

peter - 2013-03-13 1:44 PM

 

Do not use silicone for this job, as it's a sealant and not meant for it. Take off the frame and remove ALL silicone and stick it back in place with Sikaflex 221 or other suitable adhesive / sealant.

 

thanks was not sure what to call the translutant stuff, sealant is a good word. how do i remove it?

[Derek Uzzell]

You can buy silicone remover

 

 

but it shouldn't be that difficult to get off if you are going to remove the hatch. Most of it may come off if you can find an 'end' and pull, and scraping with a bit of soft wood should remove the rest. As Peter advises, whatever sealant is used subsequently, you need to remove all the old sealant to obtain clean surfaces on to which the new sealant can bond.

[Brian Kirby]

I think you need to investigate a bit, Caroline. I don't think silicone sealants are standard for this kind of use on motorhomes, which suggests to me one of two things.

 

Either someone else has tried re-sealing the frame, or it is something someone has added to the van, and in either case done a poor job.

 

Derek is right, there should be a timber frame around that trap, to stiffen it, and take the fixings. I'd suggest first removing the entire trap frame, and then exploring for that timber frame. Simplest way would be to probe into the insulant with a thin steel rod, something like a skewer. Just push it in on both sides, plus top and bottom, about the centre of the opening. If the timber is there the probe will soon hit it. If it penetrates more than an inch or so, there is nothing there. If that is the case, it will explain the loose screws, because they will have been driven into the (presuming they are internal) very thin wallboard only.

 

If that is so, to get that trap frame securely fixed, you'll really need to cut away the insulation all around the opening to sufficient depth (about one inch, maybe a little more, and insert wooden battens to completely fill the space between wallboard and outer skin. These will have to be carefully cut to an exact fit, and then glued into place with a high adhesion waterproof glue, or better, an adhesive sealant (the Sikas as mentioned above would be fine). Then place further battens both sides of the van wall, and cramp these into place to pull the outer and inner skins into close contact with the batten you are gluing in. While the adhesive is setting, clean all traces of old silicone from the frame. Then, when the adhesive has set, remove cramps and additional battens, carefully clean up all traces of adhesive and old silicone, and re-insert the cleaned frame onto a new bed of adhesive sealant, replace the screws, and tighten gently to just begin displacing the new sealant bed, and carefully remove any surplus to leave a smooth finish. Wet finger is a good tool, but check sealant for irritant properties. When the new bedding has set, just give the screws a gentle further twist to just nip the sealant bedding and hold it compressed.

 

If there is no frame and you omit to insert one, I think you will have repeated problems with that trap.

 

If there is a timber frame then, as above, remove the trap completely and clean off all old sealant. See if the existing screw holes have just suffered from someone over-tightening the screws. If so, take a match-stick or two and gently tap them into the old screw holes with a little waterproof woodworking glue to fill the holes. When the glue is dry, trim back the match-sticks flush, re-fit the hatch frame on new sealant as above, and screw back as above - but don't over-tighten the screws! Neither will be a difficult as it sounds! :-D You'll just need dry weather - and more warmth than we presently have.

[Guest peter]

Blimey, that seems like a lot of work. Why not forget about screws and just sick the thing back in place. with Sikaflex Push the screws back in place so that the holes are filled and job done. I wouldn't go cutting the van about to do that. Sikaflex is strong enough to hold a satelite dish in place, so a flimsy hatch is no problem. Talk about take a sledgehamme to crack a nut.

[Derek Uzzell]

There's a section in John Wickersham's book "Build Your Own Motorcaravan" on making an aperture in a sandwich-bonded panel. JW recommends the methodology mentioned by Brian of adding a wooden frame around the hole into which screws can be fixed. It's also the technique I've used when I've cut large holes in my motorhome's bodywork.

 

There are photos of a 2008 Dakota here http://tinyurl.com/cfka7fo and it looks like the hatch doors are Thetford products. I expect there's wood behind the frame of the big under-bed hatch on Caroline's motorhome but, if the wood were missing, my (albeit limited) experience of fitting Thetford door-frames is that it may prove difficult to reinstall the Dakotas's door with nothing solid to screw into.

 

It's not a question of SIKA-type adhesives not being strong enough, just that accurately positioning the door without screws being firmly in place is likely to prove challenging. If there's no wooden framework, and the fixing screws are just going into the insulation, gobbing Sikaflex around the frame would be an unsatisfactory approach IMHO.

[crinklystarfish]

This repair could satisfactorily be done either way.

 

As Sikaflex 512 (and its peers) is pretty forgiving a decent job could be made using this product alone.

 

As before though, clean / dry everything properly first and clean up any excess Sikaflex before it goes off. You can do this by physically removing it (finger), smoothing it (spitty-finger) and a wipe around with proprietary remover (or white spirit at a pinch) to remove the inevitable dawbed remains.

 

I'd personally go the full on batten route (repairing the old / putting new ones in if required) but most 'professional' repairers would just splatter it with a tube of Sikaflex - actually they wouldn't - they'd use one of its cheaper alternatives.

[Colin Leake]

We had some screws that held the mounting rail for the table in our Rapido come loose. Injected some hot melt adhesive into the holes. Let it cool, drilled pilot holes and replaced the screws. Worked fine for me but you will need to ensure the wood that should be round the hole is in good condition.

[Caroline]

thanks all, will wait for that dry day this year and see what i can do.

 

(lol)

[globebuster]

Caroline - 2013-03-15 12:52 PM

 

thanks all, will wait for that dry day this year and see what i can do.

 

(lol)

 

Peter is right - You lot like to talk a job up don't you!

[crinklystarfish]

Peter is partly right, the advice from the other parties is equally valid. Please do let us know if there's anything else you can't really help with.

[globebuster]

Always happy to oblige :->

[Caroline]

Just thought I would say thank you, I now have a fixed locker frame and door and I am very proud of myself.

 

Took a couple of leaps of faith, but I am dead chuffed with the results.

 

Thanks for all the help your advice was really good............it took approximately 3 solid hours with another poor soul helping me. My finger nails make very good scrapers and are now in tatters !!!

 

(lol) :-D :-)

[Brian Kirby]

Well done Caroline. I confess I forgot about the nails! :-D