Realistic Flat Walking Roof Solution

My wife and I are located in the Largent, W.V. area, approximately an hour from Winchester, Va.; Martinsburg, W.V.; and Hagerstown, Md. Our house is situated in a niche within a tall limestone outcropping. The Cacapon River sits thirty feet below us, the remainder of the outcropping and the mountain within which it resides rise above. The house has a flat roof of six hundred square feet that shelters two bedrooms below. It also extends out another ten feet, directly overhanging the river’s shore. Accessing the roof from below would be challenging.

This roof also serves as a deck that is used daily during warm months. Patio furniture and a large circular wooden picnic table are located on this deck. Our eighty pound dog can often be found on the deck when we are there.

The current roof, which looks to be at least ten years old, is torch-down modified bitumen. There is at least one leak of significance with some attendant rot. Cracks are starting to appear on the roofing material. We are patching with an asphalt suitable product as we go.

Most local roofers will not touch this job. They deal exclusively in three-tab and metal residential roofing. They are not familiar with the techniques and material used on flat roofs of this type.

The one quote I received from an outfit out of Hagerstown recommended a layer of half inch IsoGard directly over the current roof, rot and all, with a final TPO covering. I was surprised by this potential solution. Everything I know about isoboard suggests that even even walking for simple maintenance purposes can lead to damage. This company refused to offer further info regarding their solution.

I have several questions:

  • Is the IsoGard solution realistic? Will it endure the type of usage we would subject it to?

  • From what I’ve read, there is no material currently on the market that can provide a simple and sound solution for such an environment. Everything is a compromise. Is this true?

  • We are in our seventies. If lucky, we probably have no more than five to ten additional years here. Is there one solution that you would regard as most practical for us when considering initial cost and durability?

  • Is there a lightweight, walking deck material that could be installed over whatever is eventually used that would provide real protection from above, but not create damage below? Walking decks of stone, etc. are not possible. The roof simply would not support such weight.

  • I don’t know if roofer recommendations are allowed on this site. If they are, I’d appreciate any that might be offered. Over the years, we’ve found roofers to be an independent lot, but one that was always willing to make an effort. Over the past five years, we’ve found getting quotes amazingly difficult both here in W.V. and also in South Jersey.

Thanks in advance for any meaningful suggestions.


Given what you’re looking for, I would think getting a quality solution to a roof that will not leak but doesn’t have to bear loads is the answer. Which means you need some type of deck over the top of it. Perhaps you should consider one of the synthetic composite materials for lighter weight.

Densdeck over insulation with walkable PVC roofing.

You will probably need to contact a commercial roofing company for this.


Agreed with Axiom. High Density WF mechanically attached, followed by Dense Deck installed with an adhesive! I absolutely would use commercial roofing contractor, as they know all the details that Shinglers don’t have a clue! Our business is strictly commercial flat work, but we do repair residential breezeways, addition’s/decks that were installed by Shinglers watching to much YouTube.

Appreciate the comments and suggestions made.

This is proving to be a difficult project for us. We are out in the middle of nowhere. Most commercial roofers don’t want to drive the hour necessary to get to us, even though I have acknowledged my willingness to pay a premium for travel. After calling many roofers, I currently have two written estimates in hand with a verbal third.

Every one recommended isoboard insulation of one type or another over the existing roof, leaks and soft areas included, with a single membrane capping everything. One recommended TPO, one PVC, and the third an as yet unspecified granulated top membrane.

The second roofer also offered another option, Deckshield over plywood with sanded seams over the existing roof. Unfortunately, given the fact that the two bedrooms are cantilevered as is the deck above and considering the fact that everything here was done thirty years ago using that period’s technology, I’d want the old roof removed. I don’t want the deck bearing too much weight. The roofer quoted a price of over $2,700 for removal of under 700 sq. ft. of modified bitumen and its plywood substrate. That would bring this option in at over $15,000 for our small roof deck. Even considering travel, that figure packs a real wallop.

I remain concerned that isoboard over the current roof would deform, especially over soft areas, when used as a deck. Densdeck sounds like a more promising alternative; but, I believe it weighs considerably more than isoboard. I read somewhere that it’s about sixty pounds an 8’x4’ piece. Again, the old roof would need removal.

If an experienced commercial roofer here has an ingenious way out of this without the need to spend a king’s ransom on such a small roof deck, I’d appreciate his sharing it with me.

Go with the PVC it is much better than the alternatives.

You absolutely need to have something rigid over your insulation if you intend to use this as a deck.

The insulation simply will not bear the weight if chairs, tables, etc without punching holes in it.

No matter what you do this is not going to be cheap, if you want to see this get really expensive go with a low bidder, that way you get to do it 2x.

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Hey Allen, What are the odds, I am in Largent area as well.

I have a similar challenge, except I am building new (garage with deck on top)

Can you contact me… I own the little store by the bridge. I couldn’t find a way to contact via the forum…

703 229 una una 39 is the number, of find us on Facebook and contact via FB.
Store email address is
(combine everything in quotes into an email, no spaces and replace at wit @)

Hi Al,
Saw your post and wondered if you ever figured out a solution. We have a similar situation. We have a 30 year old 3 story- farmhouse that has two side wings with roof decks on each end. One has interior living space underneath, the other has a patio below. Originally both roofs were covered with a black rubber roofing material (?EPDM) and the patio side had a wood deck on top. We had significant moisture issues (no flashing around doors) and a damming effect from the deck side.

In June (2 months ago) we had a contractor replace the EPDM on the laundry room side and remove rotted plywood and roofing on the patio side. Reinstalled EPDM with a deck over top on the laundry room side and just a deck on the patio side.

Unfortunately none of their work met code and we are having to tear it all off and redo it.

These porches have exterior doors so they need railings. They are used as rooftop patios with foot traffic and some porch furniture (chairs/tables). We are thinking we’d like to avoid putting wood on top due to the debris and water drainage, but need a solution that will allow us to use the porches.

What did you end up using? I’ve looked at EPDM (white for heat reflection), TPO or PVC. I’ve also looked at the possibility of vinyl decking (like Duradek, Tufdek, etc.) but we live in a small town in SW VA, so finding a certified installer for that will be challenging and it’s pricey. Since we are already out over $8K on this job + whatever we will have to pay for demo-ing what was put on before, we’re definitely on a budget now!

We’ve been told TPO and PVC are slippery and easily punctured. One contractor recommended getting rubber roof tiles/pads to put over top of the surface where we wanted furniture. Does anyone know if an indoor outdoor rug would provide enough protection for a membrane type roof?