Questions about re-sealing Heki 3 skylight

[Nixdorfer]

Hi folks, I need to tap into the MHfun fountain of knowledge

Whilst away the other weekend we started getting some drips from our Large Heki sylight on one corner.

It did stop eventually and didn't happen again when it next rained, maybe angle? anyway I decide to investigate this week.

I planned to just re-seal the outside for now but once I'd got the interior trim off to check I decided to take it out and do it properly. Possibly a huge mistake and wish i'd left it for a job over winter now

Anyway commited now and its out after a LOT of effort with a blade. Roof is cleaned off and skylight is cleaned off. It has a rubber seal fitted which i didn't expect to find, its survived removal with a few nicks so was planned on re-fitting that maybe with a bit of something on it

When built they used copious amounts of clear sealant in the channel behind it and on it which i've now cleaned off.

Questions:

I have 2x tubes of Sika 221 which i got for another project so could use that (if suitable).

OR

Am I better waiting and ordering some of this Hodgsons CV sealant.

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I consided the butyl tape stuff but the channel is about 1cm wide and pretty deep at 5mm so may need multiple layers plus the seal complicates it a bit as it sticks out proud already so couldn't really apply any over that.

Should I do way with the seal and just use plenty of sealant?, or apply a something to that as well as running it down both sides

Know these sort of questions have probably come up before but the factory seal is throwing me a bit. Expected it to just be sealant

Thanks

 

[Revolvor]

Am I better waiting and ordering some of this Hodgsons CV sealant.

I've just replaced a damaged Heki Skylight, and used Hodgsons CV Sealant, as it seemed very similar to what the original manufacturer had used, and that hadn't leaked in the last 14 years. I was suprised how easily I was able to get the skylight off with a sharp blade, and it was still flexible and VERY sticky.

Unlike some other skylights, the Heki is secured to the roof by a clamping action from the inner frame, and does not need to be bonded to the roof - just sealed.

 

[eurajohn]

Best use one of the Sikaflex butyl sealers, it needs sealing not gluing.
Tape is OK but as you've noticed the gap is not uniform, pencil mark the roof around the skylight and then use masking tape to produce a barrier for any excess spreading.

 

[Nixdorfer]

Thanks. you've both confirmed what I suspected was the best route.
Hoped might get it done over the weekend but a few days delay to do it right is worth it. Have to break it to the OH we aren't going out in it tomorrow now

The Sika 710 and the Hodgsons seem to be very similar. The Sika seems harder to source

So basically leave the seal on and fill the groove behind with the butyl stuff and a bit on the seal and let it spread, then tool it off once clamped?

Have already taped around the perimiter to reduce the mess