How to Vent 100 yo House

I have a house that was built in 1912. I live in upstate NY so my winters are cold. I am in need of a complete tear off roof. My roof right now has the original slate along with two layers of asphalt over the top (miserable). This is going to be a big job as my house is 3 stories (attic included) with a dormer on each side of the house. I want it to be done right so here is my question…

My house has over 3’ wide tongue and groove eaves, no soffit intake. How do I vent this roof?

My attic is about 1000 sq ft with finished plaster and is conditioned space. There is a knee wall where I can access a crawl space to see the lower portion of my roof. This crawl space is not airtight and is cold in the winter, warm in the summer. Currently no ridge vent installed.

A couple contractors want to install 3/4" furring strips over my existing tongue and groove decking, then re-deck over that. They would cap that at the end with vented drip edge and that channel, along with a ridge vent, would create my venting solution.

Thoughts? Are there other options?

That’s known as a cold roof. As long as they underlay the deck before the furring strips it’s the best you can get. I’d have them also bid drywalling in the side attics and blowing insulation between the ceiling and the existing deck after tear off and before the new deck. I’ve done a couple dozen in northern Indiana, and everybody was pleased. No more ice dams and the house was a lot warmer in the winter.


Are you going back with shingles or slate? Slate does not need vented.

Not all shingle roofs need vented either. Although yours may not be designed right for that since it was originally slate.

Since you have the open space in the attic at the eaves you could install new soffit vents and ridge cap. They make rectangular and round vents, you don’t need to replace the soffit completely to ventilate it.

If you don’t like that you can install deck vent as well, or vented drip edge by cutting a strip out of the deck/fascia respectively.

Installing the furring strips and wood sheathing is also a great option, and probably the one that will most reliably not result in condensation issues.

We are looking at replacing with Asphalt shingles, possibly Certainteed Belmont or Highland Slate. I should have mentioned earlier but we have a hip roof. Our eaves are exposed rafter tails so, I assume, what I am seeing on the underside of the eave IS the roof deck itself. Our roof deck appears to be 1" x 6" tongue and groove where the eaves are smaller width tongue and groove.

Would it be best practice to install hip vent(s) on the front and back side of my house that does not meet the ridge?

I am beginning to think that this cold roof option is my best choice. is 3/4" over the original decking enough space for adequate air flow?

2001, I installed a decking on an A frame home. The cavity was stuffed with insulation, but still not enough for heat and cold. We installed a product that had 1x2 incorporated into the Plywood. It was made in louisiana and we bought it thru Cameron Ashley building products. I can’t remember the company name, but a quick internet search, I found VENTBOARD looks like the same type of product. I would look at the cost of buying their system. We were able to buy ours in 10ft lengths. Maybe VENTBOARD makes it in 10’s.

If there is attic space near the ridge, You can use box vents.

The furring strip is probably the bet you can do. 3/4" is more than enough space for venting. If you want to insulate the building you can also install vented nail base insulation.