In reply to message posted by Robert Stephen Morton:
Bobert. Its hard for us Ausies to be offended because even our mates put crap on us.
Sylvan. Thank you very much for your reply, however you are talking a foreign language regarding the roof coverings, there are no parapets or scuppers, this roof is a simple low pitched roof 5deg with a ridge & external gutters. The sheets are 21 metres long Zincalume & all are in absolutely imaculate condition exept the sections sprayed with this foam overlay, the A/C units are placed on stands which are supported by metal frames that penetrate the roof & are bolted to the structure, even those metal frames are rusting, if I put my foot on the foam I can hear the metal crackling under my foot, indicating that I should not put my full weight on. Have you any information regarding the product & has there been any other repercussions over in your foreign land, Foreign because its full of Foreigners & not Australians! (except a few like yourself)

Steven, I had no intention of offending anyone just stating a fact.

There are way to many bums out there foreign and domestically bred that have no clue to what is the proper job.

Now you mentioned metal frames which support the AC units rusting plus the metal decking under foot cracking.

OK is the “metal decking” corrugated steel with a zinc coating (galvanized steel)?

The AC frames maybe uncoated mild steel setting up an electrolytic condition where dissimilar metals come in contact.

This is especially true with water present like wet membrane etc.

For example even in this country there are certain roof membranes I cannot use lead for a flashing material or even bitumen as it will react with the new polymer types of roofing single ply systems.

I would suggest using either hot applied coal tar enamel on the exposed metal with a covering of 15# fiberglass felt.

Of course the old stand by is several coats of red lead paint and an anode to take the brunt of electrolytic action happening here much like the ones found in a hot water heater or mixing ferrous and non ferrous metals

I am not familia with your term “Zincalume” but if zinc is present this could be a major factor in your deteriorating under roof metal failing.

We find the same thing here when idiots have no clue when installing piping penetrations through a corrugated galvanized decking without taking precautions.

There are many types of roofing systems on the market and lots of defunct manufacturers of materials also.

Have you thought of asking the building owner for a canceled check made out to the roofing installer then contact them.

Or check locally as to who may have carried this material.

Mixing membranes can be very risky as one will eat up the other.

Some of the oil based (tars) destroy the non petroleum types therefore you should contact the local roofing association to find the manufacturer of this foam material to find what it is compatible with.

You mentioned a ridge on this roof is it metal or wood covered with mastic?

If it is wood was this wood nailed down and allowances made for expansion and contraction as this also can cause a premature roofing failure?

The building movement can crack the membrane and allow water infiltration through fish mouths or alligatoring due o the sun effects

What kind of materials did they use around the roof penetrations as some blokes use what is commonly called a “pitch pocket”

which is nothing more then a sleeve, copper, cast iron or stainless filled with some type of bitumen that needs replenishing and if this foam is incompatable this also could be the problem.

Dont you just love these challanges?


» This message has been edited by SylvanLMP on 06 December 2001

» This message has been edited by SylvanLMP on 06 December 2001

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