Armaflex through roof - insulation on or off?

[pdf27]

I'm planning to use 20mm "Armaflex" (well, probably a cheap knock-off - current plan is to pick it up in Germany when we go there later this year to visit those relatives who couldn't make our wedding last summer) to connect directly from the pumping station to the panel on the roof. Will there be a risk of leaks if I leave the insulation on where it goes through the rubber feedthrough in the tile, forcing me to strip back to the stainless tube at this point?



All the photos I've found show no insulation at the feedthrough and it being added on afterwards, but this will presumably leave a cold bridge through the rubber feedthrough section. I'm struggling to see much of a risk of water seeping down the entire length of the inside of the insulation and giving me a major leak in my airing cupboard when it rains, but thought I ought to check why nobody else seems to be doing this before finding out the hard way!

Note: mods, please delete if this breaches site rules about mentioning other suppliers...

[pmagowan]

 I would personally be more worried about leaks than the small area of poor insulation.  All the instructions say to use grommets on bare pipe.  You would be surprised how water finds a way in.  You could maybe use some high temperature squirty foam inside the grommet to seal it but this would effectively glue everything together pretty permanently.

[Drawmer]

I used this system.

The rubber grommet is only a few mm thick.
Make the actual hole through the tile a fair size, and push the insulation up into the tile hole from underneath so that the rubber is pinched inside and outside between the insulation. In this way the thermal bridge is only the rubber grommet - not bad at all.

Birds like armourflex - cover it with something to stop them. I used yukky messy Denso tape. Others have made really smart covers using 75 or 100mm rainwater pipes.


taped up by pdrawmer, on Flickr

[alankelly]

Hi PDF27

I would do the same as the others suggest and insulate either side of the pipe and only pass the bare pipe through the silicon boot to avoid possible rainwater leaks.

When I did my installation last year, I used the same silicon boot / tile arrangement as yourself, and for the "inside" of the roof, the Armaflex insulation covered the pipe (In my case 12mm S/S Twinsol) right up to where the pipe entered the boot itself. And for the "outside", the pipe was covered first with Armaflex, but then I surrounded the whole set up with an electrical enclosure sourced from RS which has been stuffed with Rockwool to futher increase the insulation of the outside pipes.

(Idea taken from Antmans install. Thankyou Antman  )

Just ensure you used high temp' silicon seal all to prevent water ingress into the enclosure

This setup makes the install / outside insulation very neat, and more importantly bird proof and UV proof (As UV can degrade certain types of foam insulation if exposed for long periods of time to sunlight) And with this set up the enclosure is large enough to insulated / cover my manual bleed valves.

See photos below

So as per the other replies, the only part where the pipe is uninsulated is just where it passes through the boot itself, so only creating a very small thermal bridge and reducing the posibility of rainwater leaks.

Best and kindest regards Al.

[pdf27]

So recommended procedure is to drill hole in tile to roughly match insulation size, strip insulation back down to about tile level (possibly using some sort of gunk to hold the tubing in place if needed), fit tile/grommet, refit insulation above grommet (pushing down so insulation is touching grommet on both sides) and fix pipe to panel. Cover with mechanical protection to keep birds off the insulation (probably inclined towards drainpipe/water pipe.

Now I just need to work out where to get my paws on a big enough car to fill it with all the wine, beer and sausage my wife will want to bring back from the trip (she used to live in Munich).