Low-cost deck roof construction

[DaveC426913]

I'm looking to roof over my backyard deck. I have particular desires for it.
It must
- let in light
- be rainproof
- not reflect sound well
- be bug-unfriendly (more on this)

Most of the materials that are transparent and rainproof are also hard, and thus reflect sound efficiently, meaning it definitely sounds like you're under a roof. This defeats the purpose of being outdoors.

As for bug-unfriendly, it merely needs to be not impossible to clean.

One thing I've thought of is to use Palram acrylic panels:

I've got them over my carport now. They're OK but very noisy.

I thought of hanging a layer of canvas panels to dampen the sound, but then they become bug magnets (got LOTS of spiders already, putting up a gap like this will fill with spiders until the roof is opaque!) So it's got to be arranged in a way that doesn't encourage webs, and also allows the webs to be cleaned.

Suggestions?

 

[Mark44]

I'm assuming that the roof slopes away from the house, with joists that are perpendicular to the house wall, and slope down. You could close off the space between the joists by nailing plywood to the bottom edges of the roof joists. That should seal the spaces well enough that creepy-crawlies can't get inside the closed-off area.

You should use the wavy wood strips (closure strips, in either wood or plastic) across the tops of the joists (and perp. to them) to nail the acrylic panels to.

 

[DaveC426913]

I'm assuming that the roof slopes away from the house, with joists that are perpendicular to the house wall, and slope down. You could close off the space between the joists by nailing plywood to the bottom edges of the roof joists. That should seal the spaces well enough that creepy-crawlies can't get inside the closed-off area.

Sorry. I see I have been ambiguous.

There is a roof, but no walls. The sides are entirely open to the elements.

("No walls?? But that's going to let in all but the very largest of spiders" you say...)

Well, yes. I'm not trying to keep them out. I'm simply trying to not give them a big, foot-deep, protected, stagnant airspace (such as one might find between a hard roof and a suspended layer of canvas) that they could flock to and fill with their webs and egg sacs. And if they do, at least the roof can be easily cleaned with a broom.

You should use the wavy wood strips (closure strips, in either wood or plastic) across the tops of the joists (and perp. to them) to nail the acrylic panels to.

Yes. I use them on my carport, to screw the panels into.

 

[Mark44]

Sorry. I see I have been ambiguous.

There is a roof, but no walls. The sides are entirely open to the elements.

("No walls?? But that's going to let in all but the very largest of spiders" you say...)

Well, yes. I'm not trying to keep them out. I'm simply trying to not give them a big, foot-deep, protected, stagnant airspace (such as one might find between a hard roof and a suspended layer of canvas) that they could flock to and fill with their webs and egg sacs. And if they do, at least the roof can be easily cleaned with a broom.

Yes. I use them on my carport, to screw the panels into.

I wasn't assuming there were walls. The house I used to live in had a roof over the patio. What I described was closing off the space between the roof joists using plywood. I think you could seal off that space well enough that spiders couldn't get in, using, say, silicone caulk. I wouldn't recommend just tacking a layer of canvas, as you described. Your roof does have joists, right?

Edit: It slipped my mind that you wanted the roof to let in light, and obviously a sheet of plywood on the underside of the joists would block that light. What about blocking off most of the undersides of the joists with plywood, but leaving a few square feet open, but covered with screening? One or two openings the width of a joist opening by a couple of feet long would let in some light, and should be less noisy that having the underside completely open.

It seems to me that you have conflicting requirements - admit light but cut down sound, not admit spiders, but admit light. Possibly you could cover the underside with a layer of clear corrugated acrylic panel, but seal it off well.

 

[DaveC426913]

It seems to me that you have conflicting requirements

Thus, the resortation to PF.

Possibly you could cover the underside with a layer of clear corrugated acrylic panel, but seal it off well.

The corrugated acrylic panel is the stuff that is noisy.

 

[DaveC426913]

You know what? The whole spider issue is throwing things off.

I want a roof that
- let's in light
- doesn't let in rain
- deadens sound, so it doesn't sound like I'm under a giant sheet of corrugated acrylic

 

[Mark44]

From my previous post:

What about blocking off most of the undersides of the joists with plywood, but leaving a few square feet open, but covered with screening? One or two openings the width of a joist opening by a couple of feet long would let in some light, and should be less noisy that having the underside completely open.

 

[Mark44]

What is the source of the sound that's being reflected?

 

[DaveC426913]

What is the source of the sound that's being reflected?

Voices, glasses on tables, moving chairs, forks on plates.

The sound of being under a reflecting ceiling is antithetical to the experience of being outdoors.

(Though being dry when it is raining is not.)

 

[Mark44]

In essence, being under a roof is antithetical to the experience of being outdoors, as you can't feel the rain fall on you. IMO you need to decide whether having light is more important than having a quiet roof.

 

[256bits]

You know what? The whole spider issue is throwing things off.

I want a roof that
- let's in light
- doesn't let in rain
- deadens sound, so it doesn't sound like I'm under a giant sheet of corrugated acrylic

Have you conidered an awning, such as the old fashioned roll out/roll up type?

 

[DaveC426913]

In essence, being under a roof is antithetical to the experience of being outdoors, as you can't feel the rain fall on you. IMO you need to decide whether having light is more important than having a quiet roof.

This is the 21st century. I should be able to have the good without the bad.

(Not that I mind the rain, but my laptop does, and my cigar does.)

Have you conidered an awning, such as the old fashioned roll out/roll up type?

Well, not so much with the letting the light in. The deck is about 16 feet square.

 

[Mark44]

This is the 21st century. I should be able to have the good without the bad.

To paraphrase our own LCKurtz, your deck roof can be "cheap, quiet, or well-lit. Pick any two."

 

[DaveC426913]

To paraphrase our own LCKurtz, your deck roof can be "cheap, quiet, or well-lit. Pick any two."

You give up too easily.

 

[CWatters]

Pitched tiled roof with domed light pipes.

 

[DaveC426913]

To paraphrase our own LCKurtz, your deck roof can be "cheap, quiet, or well-lit. Pick any two."

I had forgotten that low-cost was implied (via the thread title) as a criterion.
Let's remove that constraint. Let's change it to 'reasonable' cost. (So vibranium / transparent aluminium is still off-the-table, but otherwise...)

 

[Mark44]

What about my suggestion in post #4 and again in post #7, sort of making a skylight?

 

[DaveC426913]

How does making the skylight small solve anything? Why can't I just make the whole roof a skylight?

 

[CWatters]

Light pipes (aka sun tubes) have some length to them that helps reduce noise compared to a thin single sheet.

 

[DaveC426913]

But my roof has theoretically zero depth. Why would I need a sun tube?

 

[CWatters]

I see zero depth as a disadvantage. I suggest a thick insulated pitched tiled roof to minimise rain noise with sun tubes to allow light in.

Main problem is this totally fails to meet the low cost requirement.

 

[Mark44]

How does making the skylight small solve anything? Why can't I just make the whole roof a skylight?

Because the transparent/translucent roof material reflects sound -- that's what you said.

But my roof has theoretically zero depth. Why would I need a sun tube?

Your roof should be build using at least 2 x 4 joists on, say, 18" or 24" centers. I don't know where you live, but if it's an area that gets snow, the roof should be built strong enough to accommodate an appreciable snow load.

With the acrylic roofing on top, and plywood sheathing on the bottom, the sounds that annoy you shouldn't reflect as much from the plywood as they would from the acrylic roofing. Leaving one or more openings in the plywood is a compromise so that you can get some light through the roof without having the entire underside of the roof reflecting sound back to you.

My suggestion is similar to the light tubes that CWatters is suggesting, but without having to buy anything special. In any case, I'm not sure they make light tubes that are only 4" (the depth of a 2 x 4) long. Usually that are long enough to extend from the roof down through an attic to a room or hallway in a house.

 

[DaveC426913]

Yeah. Snow load will be a problem. The slope will be very shallow.
It will be attached to the house only about 10 feet up, under my eaves. And the outer edge must be about 7 feet, so you can walk under it. So 3 foot drop over 16 foot run.

This is modeled very much like my carport, which is 22' long, 10' deep and 7-9' high. 24" on-centre (because the corrugated acrylic sheets are 24"). It's held up OK.

(It'll have more uprights, this is just a schematic.)

 

[theboomboomcars]

You could use some clear vinyl sheeting on the underside where Mark44 suggested to put the plywood. You would want to have a bit of slack in it, so it moves with the sound waves instead of reflecting them.

 

[DaveC426913]

You would want to have a bit of slack in it, so it moves with the sound waves instead of reflecting them.

Not quiiiiiite sure it works that way...