Bird Baths between truss cords

[Physics]

hello

can anyone give me some ideas about bird baths (I think that is the correct terminology). My builder is building our house and I disagree with the way he wants to construct bird baths. I was thinking about putting two by fours in between the cords, drilling three-inch holes and placing screen over the hole. I am not sure what to do about the insulation though????? Do you hold the cardboard baffles back??? If that is done what about the insulation not being over the wall???? Any help in this matter would be appreciated.

Thanks

[Rich]

Bird baths? I guess I'm not up on your terminology of a bird bath.
From your explanation I assume you mean providing air to the attic space from the eaves. I've just called them eave vents.. but anyway.
If that's what you're talking about you can have the best of both worlds if you have enclosed soffits. In other words the bottom side of the overhang is covered with 3/8" rough sawn fir or vinyl. Or maybe you have boxed soffits which makes it even easier.
Anyway right on the outside face of the wall between the chords use a 2x whatever (it should be the same size as the top chord of your truss). If the top chords are 2x4's use a 2x4 on edge to block between the trusses. Now you will have a gap above the 2x4 where your baffles should end at. You can then stuff insulation right up to the edge of the 2x4 without interfering with the baffles.
Then for eave vents you can drill 3" I think and get 3" circular vents that will be placed in each bay between the tails of the trusses. If you have boxed vinyl soffits they have one panel per 3 panels that will be perforated.
I hope that helps.. well that is if I'm talking about the same thing. :D

[Physics]

hi,

thanks for replying. I guess I was a little vague in my question. I am talking about eve vents. I think we are building boxed soffits?? (the ends of the cords of the truss are exposed from underneath. I do not understand what you mean by "place the 2x4 on edge to block between the trusses. Now you will have a gap above the 2x4 where your baffles should end at. You can than stuff insulation right up to the edge of the 2x4 without interfering with the baffles." ????

I am assuming that what you mean by on edge is the "4" inch part up??

If that is the case and the three-inch hole or whatever is drilled and screen placed over the hole. How would you create a vent if the insulation were pushed right up to it?? Maybe the cardboard baffle does not go flush up to the 2x4?? If that is the case, than the insulation does not cover the exterior wall???

I hope this time I have been a little clearer??

Thanks

[Rich]

Here is what a boxed soffit is with what you're describing. You'll see that the baffles come to the top of the 2x blocking at the edge of wall and the insulation stops at the edge of the 2x blocking. Personally with a box soffit I would get rid of the baffles all together and put the insulation in the ceiling and use the whole attic space for air flow. That way you aren't heating and cooling the attic space.. that is unless there is a good reason for having the insulation in the top chords.
I put both areas for insulation in the drawing - do not put insulation in both places - one or the other.
Now if you don't have a boxed soffit like I'm showing in the drawing then delete the soffit framing (as called out) and do everything else the same. Air flow goes in over the top of the 2x blocking through a bird / bug screen directly into the baffles or as I suggested into the attic space without baffles.
Box Soffit (http://www.construction-resource.com/images/projects/boxsoffit.jpg)
Hope that helps clarify what I was talking about. Let me know if that matches your situation.

[Physics]

Looks as though I describried the wrong situation to you and you are probably going to think I am a nut???

Thanks for the drawing, pictures are a lot easier to describe things and I wish I had a picture to give to you. We are not building box soffits. The cord tails are exposed. If you were to remove "the box soffit framing" that is what our situation is.

Where my confusion starts is how to get the air flow if the eve vent is placed on the wall? If insulation is placed over the wall (which I am assuming is the proper thing to do) this would limit the air flow??? Unless there is something that I am missing with the baffles??? Is the baffle held back a little on the wall to let the air flow between the eve vent and insulation???

I wish I could take you to lunch or someting and discuss this. Hopefully I am describing this better, I know I am doing a poor job.

Thanks for your help with this matter.

[Rich]

Nothing really changes from the drawing other than removing the soffit framing. The air flow goes up over the "2x blocking" between the trusses and right into the baffles. The baffles are typically only 1.5" thick and air tight to the underside of the roof sheathing. Therefore it doesn't conflict with the insulation all that much.
Honestly even if the insulation doesn't get right over the top of the wall it's not going to be the end of the world. The "wall" insulation will take care of most of that along with the wood itself.
Again wherever you put the insulation it doesn't matter - beneath the baffles or in the ceiling. I personally recommend to go in the ceiling as you can get more of it in there.

[Physics]

boy have I been an idiot, sometimes I get some pre-determined thoughts in my head and I can not get rid of them. For some reason I thought the cardboard baffle was folded the same width as the 2x blocking and placed in front (inside of attic side) of the 2x blocking to create the air gap.

I see exactly what you are talking about now. How do you fasten the bug screen to the 2x blocking and/or roof sheeting?? In additon, do you attach the baffles to the 2x blocking?

Thanks for your help and sorry for being an idiot!!!

[Rich]

That's not a problem Physics. I do the same thing more often that I care to admit. For the bug screen I'll typically staple it to the 2x blocking and the underside of the roof sheathing. If you want it to look better than some old shack you can use some paint pine strips to wrap the screen around and then staple through the pine strip. Then it looks like a piece of trim instead of some ratty screen.
Typically the baffles are not attached to the blocking but only to the underside of the roof sheathing.
Hope that helps.

[Physics]

Thank you very much for your help in this matter!!!!!!! I get to put the blocking in on Thursday, good way to bring in 04.

Hope you have a wonderful New Year and people like me do not ask you any more stupid questions!!! But I will probably be back on this in another week with more stupid questions???

All the best

:D

[Rich]

No such thing as a stupid question. I set this forum up to help people.. so without the questions there would be no reason for the forum..
Hmm.. the chicken or the egg. :D
Good luck with everything.. and Happy New Year to you and yours.

[jjcold]

I didn't read all the posts (probably should of, eh?) but I think what you are talking about is "bird blockers" the 2x4 with three or so screen covered holes in it that spans between the truss bays and sits on top of the wall top plate? My builder is putting them in the house right now, I notice they install them before putting the sheathing on. they are premade.

BTW, the starlings love to peck the screen out, so be prepared to have to rescreen them all in a few years.

[Rich]

Bug screens, bird screens, vent screens, and just plain old vents, are all terms I've heard them called. I've also heard other not so choice terms when installing the heavier gauge screens.. haha.