Historic home roof replacement


#1

I own a house that was built in 1877 that I am trying to restore to what it may have looked like when it was originally built. It currently has two layers of asphalt shingles. I’m guessing it originally had a tin/metal roof. I have received three bids to install a metal roof with all three having different opinions. Two want to install 1"X4" wood strips over the existing roof and then the metal. One recommends installing Palisade synthetic underlayment over the existing roof and then the new metal roof - no wood stripping. I have also added Icynene insulation(spray foam) under the roof deck in the attic. None of the roofers thought this would be a problem but I’m not sure they have seen this before. One even tried to sell me vinyl siding more than a roof. Price is not my main concern but having it done right is. My question is the underlayment method better that wood stripping? Is there a conflict with the foam insulation? Any opinions or recommendations are appreciated.


#2

Hi,

I would not use any of them. Going over 2 layers of shingles is not a good idea.

Are you using a standing seam panel or metal shingles?

You will probably have some straightening to do. Otherwise you may have some dips in the finished product.

Do not be in a rush. Paying someone to do it right the second time is costly.


#3

[quote=“Lefty”]Hi,

I would not use any of them. Going over 2 layers of shingles is not a good idea.

Are you using a standing seam panel or metal shingles?

You will probably have some straightening to do. Otherwise you may have some dips in the finished product.

Do not be in a rush. Paying someone to do it right the second time is costly.[/quote]

Still haven’t decided on what type yet. I really like the look of metal shingles but this is an old farm house so I think the standing seam would probably be a better match. The roof appears to be fairly straight, no obvious dips. Only one of the three quoted tearing off the existing roof as an option, he didn’t recommend it though.


#4

you should always in most cases tear off the old roof.
You should try to find out what the roof was when it was built.wood shingles,slate or metal. many roofs in the late 1800s were an interlocking metal shingle as well as standing seam. Ashpalt shingles also started in the late 1800s as well. Bird and Ruberoid were the first, it was made on a heavy rag felt.


#5

Re: Spray foam on the underside of the roof decking in the attic…what for??? but since you’ve done it already be aware that depending on r-value of foam added and whether or not you incorporated free ventilated air space between decking proper and new foam spray-you might be raining inside your attic regardless of what kind of roofing system you install
Re: New Roofing system…definitely remove ALL existing roofing down to the deck and check for rot in the structure &/or deck-you’ll probably find it…so fix this condition first and then put on the roof…you’ll be happy you did


#6

This may seem too simple and uncomplicated but what we would do is tear off the shingles repair any damaged wood, lay down RooftopGuard II to the entire roof and install Galvalume (21in panels).


#7

[quote=“ROOFING MAVEN”]Re: Spray foam on the underside of the roof decking in the attic…what for??? but since you’ve done it already be aware that depending on r-value of foam added and whether or not you incorporated free ventilated air space between decking proper and new foam spray-you might be raining inside your attic regardless of what kind of roofing system you install

Thanks for the reply. We used the foam insulation because it was the only way to install insulation in the exisitng walls. Also the attic is completely sealed - no ventilation at all. You can go in the attic on a hot summer day and it will usually be about 15 degrees warmer than it is in the house. I have worked in other homes with the foam installed under the roofing deck and haven’t noticed any condensation issues. I think you guys have convinced me the shingles need to come off.[/quote]


#8

In my Area homes that were built in 1877 have very ‘unpretty’ decks. The way the lumber is milled they got as much lumber as they could from the tree. The 1X’s aren’t rectangular. You can see the edge’s of the tree. The are not squared off. This is when they would use a portable mill. Makes me wonder how many nails will be hitting air.

Some are worse than others… I guess what I am trying to say is I would think about re-decking.


#9

Luke, remove the shingles.

You might be able to figure out what the original roofing was if you can get into the attic and look at the underside of the roof boards. The original nails were probably square cut and if they are in a pattern the roofing could have been metal shingles or similar. If the pattern is random the original shingles were more likely wood shingles.


#10

HaHa, that’s too easy. The quotes I received included 36" panels. I have been looking at job pictures and like the look of the 24" better. I would like to go to the manufacturer for a recommended dealer/installer in my area. What manufacturer would you suggest for the 21" or 24" panel?


#11

where is hvac at again.

gweedo.


#12

My understanding the attic sealing already sprayed? then you must have already viewed the roof decking for its condition, I would suggest taking the existing roofing off down to roof decking, install ice &water shield where needed, the proper base sheet underlayment(felting), then Metal Standing Seam Roof System, Typically 18" wide panels, with accessory flashings.

This based on information only, consider roof pitch.


#13

Thanks much. We have determined the decking is in good condition and there is only one layer of shingles. The roof over the front porch did have 2 layers which we have removed and installed roofguard underlayment. I’m leaning toward the 5v crimp because of the “older” style. I appreciate everyone’s help.


#14

LUKESTER
5-V is an “exposed” fastener system.
In Gettysburg you see 24" O.C. 29 ga DXL (double cross lock) systems with NO exposed fasteners.
Personally, I’m just a little leary of exposed fasteners.
I would invite you to investigate some of the concealed fastener panels, such as Atas’ Standing Seam Shingle for the “double lock look”.
Good luck,
Spike