Aluminum soffits and air traffic control

[Gordon Maney]

I have a downstairs room, added when I did my basement in 1994, that has never gone beyond the rough framed state. It has just been standing idle. OK, so.... 12 years is long enough, I want to start working to finish it.

It has a roof over it, meaning it is not directly under a second floor. There is an aluminum fascia and soffit system that is part of the roof. Given how these aluminum pieces fit together, there is apparently some gap, or gaps, allowing flies to enter. In the fall, such as now, it gets pretty densely populated in there.

I have been looking at installing metal screen to prevent such insects from getting into what will be the attic space in this room. I say, what will be, because currently there is no ceiling, so they come into the room.

I have looked at it and think that all I can do is laboriously construct little wood frames, fitting them to the spaces between the overhead joists and rafter ends.

My question is this: Do you have some other neat idea of how to do this, given circumstances created by typical framing details?

Discuss....

[Sickcall]

Gordon, there are vent screens made to go between the rafters in place of the blocking on the top plate. Can you post a picture, it would be more helpful.

[Gordon Maney]

Gordon, there are vent screens made to go between the rafters in place of the blocking on the top plate. Can you post a picture, it would be more helpful.

OK..... here you go....

[Sickcall]

From just looking at the picture it appears that your rafters are 24" oc. You can purchase manufacturered metal framed screens for these openings. They are usually galvanized, I think made by Simpson, at least here on the west coast, and easily nail into place.

What is your plan for the final finish of the space? Are you going to drywall the ceiling and insulate the overhead? It is not necessary to vent every opening between the rafters, maybe every forth opening and just solid block the rest. If it is enclosed then the space will be required to have ventillation to prevent moisture build up and possibly dry rot.

If you don't like the look of the full screen opening you could cut your own bird blocks, drill three 2" holes in each block with a hole saw (on a drill press if you have one), and staple screen on the back side of the block. If you wanted a more custom finished look you could quarter round the holes with a router and use brass screen. Put the screen on after they are painted. Make sure the blocks are all square and straight in appearance from the exterior and use a nail gun to pin in place.

If this all sounds like too much work my suggestion then would be a couple of Shell No Pest Strips!

[JimmieD]

Y'know, Gordon, that must be one of the all time great thread titles! Ha hahaha...

Shell No Pest strips might work, but you could also while away your hours in there with a B-B pistol and a flashlight on long bug-ridden summer nights and improve your aim! Wouldn't even need the flashight on fireflies....

[MoparNorm]

OK..... here you go....

So... we're looking at the gap between rafters, top plate and sheathing, where the critters come in?
Normally that area is solid blocked, are those 2x6's? If so and the gap is bigger than 5.5" you can rip the blocks from a 2x8 and then cut them to size and after installation, caulk the perimeter of each block, that should do the trick.
Normally the metal vent advice would be spot on, but here are my concerns: If the exterior aluminum siding is solid, there is little reason for adding vents, as there is no need for an air exchange. If the flies are small, the mesh size of the vent or screen, will allow some of them to still enter. Just block the opening in solid and be done with it. This type of connection is normally required to be blocked anyway, to prevent shear forces (siesmic or wind) from destoying the connection.
MN

[Gordon Maney]

The aluminum soffit system is ventilated, to allow air to enter the attic space and leave via passive roof vents.

I have checked with two local yards and neither has even heard of these manufactured pieces with screen. I will google the Simpson line, and also phone some other yards.

Norm, I think I like allowing some air to flow, but the blocking would work for much of it.

[Ron in Indiana]

Gordon, since we are so close to the onset of winter and I doubt Iowa has a siesmic code to follow I offer this suggestion. Cut some batt insulation and stuff it in the spaces, this is the common practice anyway after installing air baffles against the bottom of the sheathing, just forgo the baffles until you are ready to finish the room. Even if you take the time to perfectly screen this area I'm sure the flies will find a way into the space. The only true way to keep them out is to finish at least the ceiling. As for using attic space for storage I always discourage people from doing this for several reasons.

[Sickcall]

Example of a rafter screen

http://www.heatingandcooling.com/cat...etmetal_m5.pdf -

[Gordon Maney]

Example of a rafter screen

www.heatingandcooling.com/catalog/NSI/sheet%20metal/nsi_sheetmetal_m5.pdf -

I am struggling to see how that is installed. Not from the side viewed in the photo? There does not seem to be the right combination of surfaces there.

[MoparNorm]

http://www.strongtie.com/ftp/fliers/F-RETROHC04-web.pdf#search='rafter%20%20soffit%20vent%20simpso n'
That's a standard flush fit screen, they come in different configurations, or you can add nailing blocks at the side and top perimeter of the opening. I'm baffled that your lumber yard doesn't know about these, they are standard procedure for all areas of the country. Home Depot should have them. You only need one vent every 8'-10', it's just for releasing pressure in the event of a wind shear or tornado, or wind loads above 60 mph. All the rest of the openings should be blocked and caulked.

MN

[pieter]

I don't think that is exactly what Gordon needs... maybe a picture from the outside would help everyone understand. I believe from his description, the outside is finished and already has vents. Being that there are gaps in the finish material, fly's are entering the enclosed space.

Gordon, can these gaps be closed? Are there lap joints(in the sheetmetal) that you could run a few sheet metal screws in with maybe some caulking to seal things up better.

If you can't do anything like that, take Ron's suggestion and fill the cavity with insulation. Or you could block it all out with wood.

Pieter

[Gordon Maney]

Yes, the outside is finished; enclosed with aluminum soffitt. Anything I do must be done from the inside.

The Strongtie literature shows a frieze vent. This must be a comparable application to the piece that Sickcall posted. The Strongtie literature illustration leads me to believe that the screen was put in from the outside.

An interesting, related matter is that the building supply houses sell pieces that go between rafters and extend down toward the soffit, to keep that space open, free of insulation, so that circulation can occur.

[Sickcall]

Gordon, without a picture from the outside it was hard for me to determine from your post what your exact need was. These standard rafter screens which are commonly available, as Norm pointed out, can be installed from the interior and used in combination with the existing screen system that is ineffective. I think thats a judgement call on your part.

As far as the need for attic ventillation, at the bird blocks up thru the ridge vent, you should do a search on the web as there are many pages of information discribing the requirement. Moisture needs to be removed to prevent mold and dry rot under the roof membrane. As far as I know I beleive it is also code, at least where I live.

[Ron in Indiana]

Gordon the pieces you saw are the air baffles I was refering to which allow air movement into eaves and out the roof vents. This is needed to vent the attic space of heat and to lessen the chance of ice dams in the winter. The baffles are usually styrofoam in a pan or zig zag shape and are stapled to the underside of the roof then batt insulation is stuffed between those and the top plate if you are using blown in insulation to keep the insulation from entering the overhang. If you do install the screens you should still install the air baffles when you insulate which will mean you will destroy the screens to properly install the baffles. I stand by my previous post for your problem. Thank you.