How to cut out for continuous eave vent

[rquackenbush]

I'm in the process of insulating my garage. I have large gable vents, but no eave vents. My plan is to install continuous vents on both sides of the garage. The problem I'm running into is not having a lot of room to work...

The ideas I've had so far:

• Use an oscillating tool to make the cuts. Is this feasible for 160 linear feet of cutting?
• Use one of the small handheld circular saws (e.g. SawMax). Not sure there's enough room to fit it up there.
• Take the eave board out and cut it on a table saw. This would take a lot of work and I don't want to damage the siding in the process.

Any other ideas?

 

[smschriefer]

Why not go with 4" circular eave vents? Is there a reason you want to do the whole length?

 

[smschriefer]

Here is an example that is real easy to do as it is a 2" hole - price isn't bad either.
http://www.lowes.com/pd_244086-5259...8_4294937087_?Ns=p_product_price|0&facetInfo=

 

[Jason641]

If you want it to look good and be straight i'd take it down and use a table saw. Easiest solution would be to drill 3" or 4" holes and use either round vents that fit in the holes or rectangular vents over the holes.

 

[rquackenbush]

I looked at doing the circular vents. When I calculated it out it looked like I as going to need about 50 to get enough air flowing. That's a lot of holes! That still might be easier than taking down the eaves.

 

[pattenp]

How about the square type? Cut out with jigsaw.

 

[rquackenbush]

If I could fit a jigsaw up underneath that eave, I'd have no problem!

 

[madstat]

It's hard to tell exactly how big that eave is, will one of these fit under it?

http://www.cordless-drills.net/dewaltheavydutycordlesstrimsawkit538inch144volt-pi-732.html

I have this saw it's quite small and light and I've used it in similar pinch type situations.
If this kind of saw fits, you could use the existing trim at the top course of siding as a fence to get a straight cut. Then rip an auxiliary piece of wood on the table saw that is the width of your strip vent. Place the auxiliary piece against the existing trim and make a second pass to get two perfectly parallel cuts the exact width you need.

best of luck.

 

[rquackenbush]

That looks a nice saw, but it won't fit. I'll try to take a better picture of the area I'm working in... It's pretty tight.

I do like the idea of the guide board - thanks.

 

[Falcon67]

How about the square type? Cut out with jigsaw.

you could try this type, except using a 3" hole saw to make overlapping openings where the screen mounts.

Or - remove your soffitt and replace with LP SmartSide vented soffitt.
http://www.lpcorp.com/smartside/soffit/

 

[caseyr]

you could cut it with one of those vibrate type saws that Rockwell makes

 

[pattenp]

Yeah.. I see now that your soffit board is narrow and on a slope. I didn't realize what you were dealing with until I took a second better look at your picture. A Rotozip with a saw blade may fit.

If I could fit a jigsaw up underneath that eave, I'd have no problem!

 

[dartsportsteve]

Would a variable angle reciprocating saw fit?

 

[madstat]

That looks a nice saw, but it won't fit. I'll try to take a better picture of the area I'm working in... It's pretty tight.

I do like the idea of the guide board - thanks.

If we knew the pitch (10/12?) and the overhang (horoz dist from fascia to siding) we could to an exact calculation. Keep in mind you can tilt the sole plate of most saws to just over 45 deg, this allows you to keep the body of the saw mostly vertical and away from the siding which appears to be the problem.

BTW, I hate doing this kind of over head cutting as I always end up with sawdust down my shirt. If taking the soffit off is not too much of pain that's what I would do.

 

[James E]

Part of the problem is that with the continuous vent, the edges of the cuts are visible even after the vent is installed--that means that a reciprocating or jigsaw cut would look terrible, forever. Continuous vent tucks up under the soffit boards so the cuts show even after installation. You'll also have to paint the edges of the boards where you cut.

Reciprocating or jigsaw would also run into the horizontal framing members that hold up the soffit. The only real option for cutting the soffit in-situ is a circular saw with the blade set really shallow.

Unless you can get a circular saw up there and cut a really long, straight line, I'd suggest you pull the soffits down and cut them on sawhorses.

Or switch to another type of venting system.

 

[tcianci]

What makes you think you need the vents in the first place???

 

[Justanoldguy]

What makes you think you need the vents in the first place???

my thoughts as well.

 

[pattenp]

That's just the proper way to vent roofs to help prolong shingle life. Improper ventilation or lack of can shorten shingle life plus may void some shingle manufactures warranties.

What makes you think you need the vents in the first place???

 

[darkk]

A toe-kick saw would work for that ...
http://www.harborfreight.com/3-3-8-eighth-inch-blade-toe-kick-saw-94626.html

 

[brownbagg]

rip the plywood out with crow bar and then screw two 1x4 in its place

 

[tcianci]

That's just the proper way to vent roofs to help prolong shingle life. Improper ventilation or lack of can shorten shingle life plus may void some shingle manufactures warranties.

The OP says he has gable vents. Soffit vents were developed to work in conjunction with ridge vents to take advantage of natural convection to aid in ventilating the attic space. They are also considered part of "cold roof" construction that helps to eliminate ice dams by keeping the back side of the roof sheatiing as cold as possible to prevent melting of roof snow on the roof area where the roof deck is closest to the conditioned space. This doesn't automatically make gable vents obsolete or ineffective. In fact if the building does not have a ridge vent, adding the soffit vents will buy him nothing. If the building, however insulated, is not heated, the soffit vents will do nothing to prevent ice dams because you need a heat source to have leakage from ice dam conditions. I asked the question because the OP has a difficult trim detail going on and his going through a lot of work to ventilate that soffit may buy him nothing.

 

[RivennHewn]

Part of the problem is that with the continuous vent, the edges of the cuts are visible even after the vent is installed--that means that a reciprocating or jigsaw cut would look terrible, forever. Continuous vent tucks up under the soffit boards so the cuts show even after installation. You'll also have to paint the edges of the boards where you cut.

Reciprocating or jigsaw would also run into the horizontal framing members that hold up the soffit. The only real option for cutting the soffit in-situ is a circular saw with the blade set really shallow.

Unless you can get a circular saw up there and cut a really long, straight line, I'd suggest you pull the soffits down and cut them on sawhorses.

Or switch to another type of venting system.

What he said.

Circle vents are ugly. Take the time and take it down.

 

[rquackenbush]

What makes you think you need the vents in the first place???

That is a great question... I'm planning on heating and cooling the space intermittently. I was under the impression that I would need to put soffit vents in to combat (as other posters have suggested):

• Ice damns
• Premature shingle failure due to overheating

The only mitigating factor that I can think of is that I don't intend to keep the space super warm during the winter.

It sounds like I'm incorrect in assuming that soffit vents will work in conjunction with gable vents. If that's the case - what are my options if I want to heat the space? Install ridge venting?

 

[djkeev]

Before cutting any vent, look at your insulation above the wall and below the roof sheathing.

Is there an air space or did the installer mash insulation in there completely filling the small cavity?

No air space? Any attempts at soffit vents, any type of vent, is a complete waste of time and money for they will do absolutely NOTHING!

You will need to open an air space if you really want to go this route.

Dave

 

[djkeev]

That is a great question... I'm planning on heating and cooling the space intermittently. I was under the impression that I would need to put soffit vents in to combat (as other posters have suggested):

• Ice damns
• Premature shingle failure due to overheating

The only mitigating factor that I can think of is that I don't intend to keep the space super warm during the winter.

It sounds like I'm incorrect in assuming that soffit vents will work in conjunction with gable vents. If that's the case - what are my options if I want to heat the space? Install ridge venting?

Other problem, wet ceiling to wall Sheetrock from condensation.

Soffit vents WILL work with gable vents! Ignore that bad advice that was given. It makes No difference if the air goes out the ridge or out the gable ends, proper sizing is what is important. It isn't aesthetics when looking at the gables so much as square inches of vent to move the air. What it looks like comes into play after you figure proper sizes needed.

Dave

 

[pattenp]

Soffit vents have been used in conjunction with gable vents long before the development of ridge vents. I should have been clearer in my post that proper venting is a combination of a Gable or Ridge vent with soffit vents.

Originally Posted by pattenp
That's just the proper way to vent roofs to help prolong shingle life. Improper ventilation or lack of can shorten shingle life plus may void some shingle manufactures warranties.

The OP says he has gable vents. Soffit vents were developed to work in conjunction with ridge vents to take advantage of natural convection to aid in ventilating the attic space. They are also considered part of "cold roof" construction that helps to eliminate ice dams by keeping the back side of the roof sheatiing as cold as possible to prevent melting of roof snow on the roof area where the roof deck is closest to the conditioned space. This doesn't automatically make gable vents obsolete or ineffective. In fact if the building does not have a ridge vent, adding the soffit vents will buy him nothing. If the building, however insulated, is not heated, the soffit vents will do nothing to prevent ice dams because you need a heat source to have leakage from ice dam conditions. I asked the question because the OP has a difficult trim detail going on and his going through a lot of work to ventilate that soffit may buy him nothing.

 

[James E]

Op, I just noticed you're in Raleigh. Obviously, Ice dams are not an issue for us here.

So you intend to occasionally heat and cool the attic--does that mean that you intend to sheetrock the space? If so, are you going to insulate the voids between the rafters? If so, keep in mind that with soffit vents, if you insulate the voids, you'll also have to insert plastic or foam air gap thingies so that there can be circulation between the soffit and the open space above your heated/cooled space. If no insulation in the voids, I think it'll be awfully expensive to heat or cool the space--especially cooling in our summers.

 

[rquackenbush]

Thanks everyone for all of this information. I'm doing the insulation work myself now... I'm putting the foam air gap thingies in (I don't know what they're called either). I'm also using kraft faced batts on both the wall and ceiling to provide a vapor barrier where hot meets cold.

That rotozip saw attachment looks like it might just fit the bill... It's lower profile than the saw max.

 

[Johnson]

I'm dealing with the same issue. Previous owner had no roof vents, no soffit vents but had 2 power fans in the front and back gable. He also have insulation batts in between the rafter bays. The south side shingles are completely curled and missing in many places. When I do the new roof I planned on ridge venting and adding soffit vents. I also bought continuous strips. It's a very narrow area to work in and I might just say forget it and just add some square vents. My walls are insulated (prior owner) and sheetrocked but I ripped out all the insulation in between the bays. My advice, if you want to go continuous, is to rip out the soffit, cut and replace.

 

[tcianci]

I know what I said sounds kinda absolute and a good point was made about making sure there is no existing insulation blocking the rafter bays, but, a soffit vent tends to work by convection and channels the air into the rafter bays so a ridge vent would be the best form of exhaust vent in that case. I admit that some ventilation will take place with a soffit vent and gable vents but it will be far from optimum. Since the OP has such a difficult task ahead of him, I would just rely on the existing gable vents and not worry about the soffit vents.