[Greenbuilding] ***SPAM*** Steel Roof Question

[Topher Belknap]

-------- Forwarded Message --------
Subject: 	Re: [Greenbuilding] ***SPAM*** Steel Roof Question
Date: 	Mon, 8 Jan 2024 20:30:54 -0500
From: 	Topher Belknap <topher at greenfret.com>
To: 	Lynelle Hamilton <lynelle at lahamilton.com>



Greetings,

If the latent moisture is hermetically sealed into the space, it would 
not be able to leak out.  If not, more moisture could of course enter.

Let's consider a sealed volume (which this is apparently not), 16' x 47' 
x 1' = 750 ft^3.  At 90°F and 70% relative humidity, equals 52 pounds of 
dry air, and 6200 grains of water, about 0.8 pounds (0.8 pints).

Thank you kindly,

Topher Belknap

-- 
Topher Belknap
Green Fret Consulting
http://www.greenfret.com/
(207) 882-7652

On 1/8/2024 9:50 AM, Lynelle Hamilton wrote:

> Hope y'all are still out here!
>
> I have contracted with someone for an addition to my home. The 
> addition has a second story with a cathedral roof. The contractor 
> insisted that I did not need decking and ice/water dam on the rafters, 
> so installed the purloines directly on them, then installed the steel 
> roof.  I have installed 3 steel roofs, but never one this way, so 
> questioned it.  He insists it's the correct method.
>
> To meet the Ontario Building code, he said we had to lay 2 layers of 
> R14 insulation, then install  foil-covered foam board (foil both 
> sides)on the inner side, seal and tape. I used Rockwook, plus RKO 3/4" 
> board as per his specs. We have not yet installed drywall.
>
> There are at least 10 areas of trapped moisture in a 16x47 foot area. 
> One is dripping onto the first floor
>
> We pulled the insulation from one area and found significant 
> condensation on the cold steel roof, seeping through the Rockwool and 
> running down the cold side of the foil covered foam board. The 
> contractor says this is due to latent moisture in the insulation and 
> that we've got propane heat in the basement. He says it will resolve 
> in time.  I don't buy this.
>
> Any advice is appreciated.
>
> Lynelle Hamilton
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/greenbuilding_lists.bioenergylists.org/attachments/20240108/04e3bd0a/attachment.html>