I need help with sheathing options. Rafters are 4' OC

I just purchased a house that needs a new roof. It is a ranch with cathedral ceilings throughout most of the house w/exposed rafters. I have had several roofers give me estimates for the job and they assured me that the rafters were purely cosmetic and I had at the very least 2"x8" joists 16" o.c. This turned out to be false, as I found out when I decided to do some demolition and removed a section of the ceiling. The “cosmetic” rafters were indeed support rafters with a spacing of 4’.
I pulled up a few shingles to see what the roof deck was made of, and it appears like a fiberboard material (homasote perhaps?).

Has anyone had any experience with this type of roof? It seems the local(Ny) roofers have no experience with it.

Any help would be greatly appreciated.

here are a few, pictures of the rafters…I could take some more photos of the roof deck, if it will help.


More pics would be nice, yes.
Chance are the “fibreboard” is insulation or donna konna (sp?).
With more pics, I am sure someone or I could help more.
What are the questions you have?

johne5

[quote=“johne5”]More pics would be nice, yes.
Chance are the “fibreboard” is insulation or donna konna (sp?).
With more pics, I am sure someone or I could help more.
What are the questions you have?

johne5[/quote]

My questions is, how can I reroof this house without reframing the entire structure? As far as I know, they don’t make plywood thick enough to support 4’ spans. This is my first house, so I apologize for my ignorance.

I will rip off a section of the roof and take some photos, later.

as you can see there is a lot of sagging above the soffit areas. I would like to ensure that this doesn’t happen again. Also, insulation is a concern.

I believe this is the product on the house right now.
homasote.com/products/Easy-Ply-Roof-Deck.aspx

There are some tongue and groove assemblies that can span that witdth, if in fact those beams are your roof framing.

GluLam makes an excellent 3" composite that will easily span this distance.

Please do take some pictures of the roof deck. You can usually do this from inside the attic.

[quote=“AaronB.”]There are some tongue and groove assemblies that can span that witdth, if in fact those beams are your roof framing.

GluLam makes an excellent 3" composite that will easily span this distance.

Please do take some pictures of the roof deck. You can usually do this from inside the attic.[/quote]

Thanks, I’ll look into glulam pricing/availability.

There really is no attic to speak of, but I’ll try to snap some pics of where the pitched roof meets the flat roof.

Hi,

The decking is tounge and groove 2x material. The homes first roof was probably a hot roof. The homeosote is some engineers dream.

When we fix these we install plywood to take the place of damaged homesote.

Their is no need to change anything. I have seen spans wider then 4’.

You are going to make problems for yourself if you try to change the framing.

Yes,i think you’ve nailed it. Its homosote.
You can still purchase it.

If there is a slight dip, i would leave it.
Its a toungue and groove material
I get mine from gulfeagle supply.
They are 8 ft long. It was about 80 dollars a sheet a couple of years ago.

edit… I am concerned that i dont see the toungue and groove seams. I think they ran them straight up and down instead of from side to side.
also they usually dont come in 4 foot widths in stock.

I think you are on the right track. You will solve this issue.

I think they also hand nailed that roof with ring shank roofing nails. Something to research before you go too far.

edit 2. There is no attic.

put a cold roof on…

He would have to run the 2X across the width and then the length? Or just width and sheet sideways?

[quote=“RooferR”]
He would have to run the 2X across the width and then the length? [/quote]

it would be the easiest and you’ll have a solid deck.

i did a church once that had 2 offset layers of true “two-by” T/G panels spread between 20 FEET o.c. rafters. You could barely drive a nail through these things…a gun was worthless…but they were rock solid…you could try some type of offset T/G pattern like that for a solid deck…

or the Homasote product is rated for 48" oc installs and would probably work fine as another forumer stated. and it’s some expensive decking

then i also say to myself beside the point…wtf do arc’s think when they are designing roofs on paper…some things are just poorly thought out.

Thanks for all the help guys. Unfortunately my architect says I need to add rafters to get the house up to code. In NY 16" o.c. is the code, and if I do any work on the house, like removing of sheathing, I need to get a building permit.
It looks like this one is going to cost a lot more than I had anticipated.
This also means I lose the look of exposed rafters, since I need to drywall over it.

I disagree. You wasted your time and money talking to that architect. Please call Roofers only and procede when you are confidant you found one that knows what he is talking about.

I would love to help you. This wouldnt be hard for me to handle at all.

You just have not found your roofer yet. This will be a job in its self. But will cost 10 times less than doing what the architect suggest.

You need a “roofing” permit. And the city inspector gets on the roof.
He wont come into the house. He wont know anything at all. It would be shocking if he even got up on the roof.

Your state liscensed roofer who understands what decking you have-- will take care of it all.

Is your ceiling a completely smooth surface?

or does there appear to be popcorn or paint, texture of some kind?

[quote=“roof-lover”]I disagree. You wasted your time and money talking to that architect. Please call Roofers only and procede when you are confidant you found one that knows what he is talking about.

I would love to help you. This wouldnt be hard for me to handle at all.

You just have not found your roofer yet. This will be a job in its self. But will cost 10 times less than doing what the architect suggest.

You need a “roofing” permit. And the city inspector gets on the roof.
He wont come into the house. He wont know anything at all. It would be shocking if he even got up on the roof.

Your state liscensed roofer who understands what decking you have-- will take care of it all.[/quote]

Thanks, I just hope I can hear those same words from a NY state licensed roofer :o
I also had the architect over to draw some elevations and map out the floor plans, so hopefully I didn’t waste ALL of my money.

The other concern is that the homasote board appears to be the only insulation I have, which is R5 I believe. At least adding rafters will give me a better option to insulate.

The ceiling is smooth and appears to be drywall affixed to the bottom of the roof deck directly.

I apologize for the lack of pictures, my camera cable is in storage…when I’m able to borrow a camera, I’ll post more.

Yes, please take some close up pics of the ceailing.

Usually you see seams where the toungue and groove homosote come together. The exposed bottem already has a finished white surface that doesnt need any paint or texture.

I havent seen it any other way, but maybe the previous owner didnt like the look and wanted to cover up the seams.

I believe i could still see the seams if i was there.
Its impossible to install drywall to the homosote.
Look in the phone book, look under roofing supply,
call them all and ask for homosote. When one of them says they have it. Go look at it personally. This will help you see whats going on at your home.

Just use some sheets of 1" marine grade plywood. :smiley:

It turns out you were right. I don’t need a building permit to replace the same sheathing.
Most of the damaged areas are above the soffit, so we’ve decided to cut the homasote away at the house line, re-frame the area above the soffit and use plywood. Hopefully there are no rotten homasote panels above the livingspace.

I do have 2 flat roofs on my house, and every roofer says their method is the best. So far my options are torch down, gaf liberty system, or epdm. My architect recommends a built up system. I also have to add insulation foam above one of the flat roofs, because it’s an exposed rafter t&g roofdeck with no current insulation. Any advice would be appreciated.