Ask The Contractors
Ask The Contractors
Question: Flat Roof & Roof Decks

It’s my favorite part of the show because I get to answer a question from our listeners. This one’s coming from Paul in Florida.

This is a great question. It might be a little confusing but I’m going to help us figure this out.

Question from Paul – in Florida
I need to replace my concrete tile roof, not a cheap prospect.
This is the Question:

I was wondering about the cost and practicality of removing the roof and replacing it with a flat roof. Then we would build a slightly raised deck over top of that?

To help answer this question I have Jarred Chappelle. He is a roofer who works for my company and he’s a great guy.

[Click to Follow along with the Transcript]

So you’ve heard the question. You’ve put on a lot of roofs. You’ve done Flat roofs, Tile roofs, and you’ve done asphalt roofs. You-name-it; you’ve done it. What do you think of this, and what would be the best path for this person to go, if, in fact, they really want a flat roof?

“I’m going to give you my opinion on a Flat Roof. There are two types of Flat Roofs… One’s that leak, and ones that are going to leak”

Todd Bird, Host of

Paul wants to put a flat roof on, and then a roof deck on top of it. How would you go about doing that?

Jarred: I would have to go with Hot Tar and Gravel. Before you put the hot tar and gravel on, you would have to put like – like on a Solar roof, you have the mounts to put the solar panels on…

Todd: The brackets that are 90° so they go upright.

Jarred: Imagine that 10 times bigger. You’ve got to spread it out throughout the roof, but it must be on rafters. Every single one of them.

Todd: So you have to hit a rafter. You just can’t, as we call it, “in the field”, which means there’s nothing underneath. Its just plywood. So you want to go to your roof rafters. That’s where you want to set your brackets, and then your hot tar which is hot, and then your gravel on top of that.

Jarred: Yes, and that way you have your mounts sticking out. With your mounts, then put your deck right on top of the mounts.

Todd: And the mounts can have holes in them, so you can drill through the side. However, that mount should be just high enough to run a screw through the [2 by 6]. Then, of course, you can jump to the next one.

Jarred: After that, you would bolt them down. Don’t screw them in.

Here is a tip:

That deck should be high enough that you can get a blower up there every once in a while to get the debris out from underneath it. It’s important that leaves are not accumulating and damaging the roof.

Todd: That sounds like the proper way of doing it.

Flat roof Install

What are the pitfalls of a flat roof and a deck on top of it? Do you see anything that’s negative about that?

Jared: First, the entrance to the deck from the house to the roof; you’ve got it really think this through. You can’t just put a deck in the open window. The walkway is the most important part. That’s where all the pressures going to be so make sure that’s the most watertight.

More than anything else, the wood is always moving.  So, remember to make the walkway the most important part of the whole roof.

Todd: That’s great advice. We’re talking to Jarred Chappelle, roofer here in the Sacramento area. Now you’re absolutely correct about that the walkway and getting to the deck. Because once you’re on the deck you’re probably going to sit on your tush, enjoy the view, and have an adult beverage in your hand. But it’s getting to and from that deck. That’s going to make a big difference. So, you really want to make sure that is done and done right.

And as always, go to the for Northern California’s best Home Improvement Pros.

Jarred, thank you for answering this question.

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