markm

Sun Nov 28, 2004 4:53 am

Hello, I could use some advice!

I have a 1500 sq ft shop behind my house that has a tin roof. The pitch is approximately 5/12. The roof will need to be replaced in the near future. I am looking for a way to insulate and re-roof all in one step. I cannot tear off the tin and do lots of construction because the shop is rented out, currently used as a cabinet shop. The noise coming through the tin roof is what I am trying to reduce. Insulating from the inside is not practical because of all the shop equipment etc. in the way.

I have done my share of construction projects so I have a fair idea of what I’m doing. I am considering using the plywood sheets with foam boards laminated to them. Do you think I can screw the 4x8 sheets directly to the tin roofing? The tin is securely fastened to the framing and is very solid. The framing consists of roof trusses 6 foot on center with 2x4s on edge on top of the trusses spaced 3 foot 6 inches apart. The tin is nailed to the 2x4s. I think it is pretty typical construction for a tin roof system. I am afraid to add to much weight or I would build a typical roof structure on top of the tin.

Any chance of my idea working? I would secure the foam & plywood sheets to the existing framing whenever possible otherwise it would be fastened to the tin. Then a comp roof would go on top. Any ideas appreciated! Thanks…

pimpingeo

Tue Nov 30, 2004 7:23 am

man, you'd think at first that that would work, but, NO!! 6 foot on center, you'd never be able to get the edges of the ply supported, and you'd not be able to fasten them down as much as they need to be, either. just hitch up your balls, tear off the tin and do it the right way, by removing the 2x4's that are on edge (perlins) and adding 2 more trusses between each pair of trusses. this will give you 24" on center, sufficient to lay the plywood on. that's the only way to do it right. and think about it, is a wood shop gonna care about a little bit of sawdust?
there is NO WAY youd'd get away with laying ply and comp on that weak structure, LET ALONE building on top of it. think about this: your roof is at least 17 square. each square of shingle material ALONE weighs 240lbs. that's 4,080 lbs in JUST SHINGLES, let alone the tarpaper and plywood, and GOD FORBID you build a structure on top of it all!! you'd be looking at 5500 lbs or so. do you really want that supported ONLY every six feet or so? plus, if you built a structure, youre going about it the wrong way AND wasting money in the process. you'd spend less to tear it off and add trusses than to humbledy-fumble !@#$ it up because you don't want to take off the tin. tin roof structure is made to hold up tin, and nothing more, THAT'S IT!!!!! just take off the tin. take it off!!!!! don't risk doing it the wrong way. what if the roof collapses on your renters, because it was too weak? LAWSUIT!!!!!!!!!!!!!!!!!
I'm not ripping your ass, I'm just trying to show you the light. TAKE THE TIN OFF!

markm

Tue Nov 30, 2004 6:51 pm

Thanks very much for the reply. Of course you are right. Unfortunately, I really can’t tear of the roof this time of year + I cannot afford a major project like that. I’m going to wait and do the right thing someday. Don’t worry I won’t add tons of weight to the current roof!

Is there anything else I can do temporarily? How about a spray on roof covering? Like the kind they put on decks? Anybody have any ideas? I’m trying to make the tin roof watertight and (most importantly) quiet the noise coming out of the roof some. The tin roof is in fair condition with no rust. Someone hot mopped all of the seams so it really has very few leaks.

Roofer05

Tue Nov 30, 2004 8:21 pm

you can use the spray on roof covering it is made by topps and after it is put on it will be 1/8" thick or thicker.

premierecommercialroofing

Mon Jul 25, 2005 1:03 am

I am not sure where you are located, but my company covers the midwest and we use a cold process spray system. The asphalt is diluted with mineral spirits and is room temperature. It is almost like a creamy peanut butter and then we embed a polyester fabric into the mastic. This is the binding agent that holds the asphalt together. We then pneumatically spray a layer of aluminum chips---approx weight about 3-4 pounds per square. These chips are made of pure aluminum and will not deteriorate as aluminum coating does. It is amazing and the results are fantastic. My name is Jeff and my number is 1-888-810-5222. we cover a five state area. IN, OH, MI, KY, IL

Master

Mon Jul 25, 2005 3:38 am

IS that a KK system?

I would recommend an SPF (spray polyuretane foam) roof with elastomeric UV inhibitor. This sytem is nearly weightless (NEARLY) and will insulate, seal, and deaden the sound somewhat, due to the characteristics of the foam.

QRFL

Mon Jul 25, 2005 3:51 am

how about polyurethane foam,that stuff insulates is waterproof and lightweight,as long as the roof is walkable,if not nevermind.,here we have only a couple of comapies who spray the stuff,maybe it wouldnt hurt to get a free on site estimate

Master

Mon Jul 25, 2005 4:45 am

Roiiiiiiight.

QRFL

Mon Jul 25, 2005 5:11 am

oh i know i know how about foam!!!!
man ineed to pay more attention to other replies sorry Master

Master

Mon Jul 25, 2005 1:07 pm

rooflife

Mon Jul 25, 2005 5:28 pm

First of all dont give up. You have more options than you think! Have you ever gave metal roofing any thought? Products like GERARD or DURA-LOK that have a batton system that would be perfect to go over your tin roof and last forever!!!

premierecommercialroofing

Tue Jul 26, 2005 5:10 pm

They are ok, but what about in the future when you have to remove the foam. ----not that easy. Also, they are difficult to get good results. In the east they are using robots to spray the foam due to the fact that just a small amount of sweat dripping off of a worker can create a problem between lifts. I am not sure how many lifts you plan to install, but delamination can be a problem if you allow the sun to get to the foam. My recommendation as far as insulation goes is to insulate your windows and your doors instead of the roof. You will lose about 75% of your heat loss through these areas. It is hard to quantify the r-value on a roof , because the area of the country you live in and also the heighth of the building affect the amount of heat that is transferred from one area to another. This is just some random information that may be helpful.
Thanks, PCR