Building felt installation

I'm intalling exterior plywood over 30# building felt. The plywood is both the sheathing and siding, per architect's specs for framing in my carport. Should the builders paper be installed horizontally starting at the bottom of a wall, with a particular amount of overlap?

 

Do you have the option of using Tyvek? Building paper doesn't breathe, and you will entrap moisture between the paper and the plywood. But if the architect calls for it, by all means, use it. Since you will only be hitting on studs, I would install it horizontally bottom to top and overlap about a foot.

 

I agree with the felt as if water gets behind it, the felt will absorb it and dry it to the outside more quickly than any housewrap. And it seals nail holes better.

A good read: http://www.umass.edu/bmatwt/publicat...iers.htmlApply horizontally as by Chandler, but only a 3" overlap is required.

Be safe, G

 

G, you're probably right on the overlap. I wasn't in gear for 30# felt. I should think an overlap of 15# to the next stud would help keep it taught.
I just don't like having the moisture trapped between the paper and siding. How long will it take to dry out. Just an observation.

 

The poster asked about the horizontal overlap, 3" on 30# or 15#. The end of roll overlap would be to the next stud back.

The water is not between the paper and siding, but as the article brought out, behind the paper.

When Tyvek is applied, the water is trapped behind the paper, as only water vapor can pass from that side (perm. of 58) In fact, with Tyvek , the water is almost trapped because of the full-length bearing the siding causes on the wall sheathing.

Typar is a far superior choice if you need, want a vappor retarder, over Tyvek. It is closer to recommended permanence (16), and 5 times stronger than Tyvek. It also has woven into it, a better water run off than Tyvek. When stapling Tyvek, one has to be careful not to pull hard as it rips easily as the fasteners, and the tighter application, the worse for the house (the folds or ripples help the water, if present, to escape dpwnward.

http://www.typar.com/pdfs/Typar_vs_Tyvek.pdf Be safe, G

 

G, my impression of "horizontal" overlap would be from side to side, not top to bottom, which would be "vertical", but I see your point, and agree.
I have used Typar as a weed block because of its permeability, but not in construction, since Tyvek is a standard. Is the construction version different?
And the way he described the construction, the interior isn't finished yet, but if it should be finished and moisture makes its way in, how will it get out, not in with the building felt?

 

30# building paper is the same thing as #30 roofing felt, right?

 

Yes, 30# is 30#, on roof or wall. The papers today are half of what yesteryears' were. Google -- tar paper or building paper.

Chandler, you are correct as I mixed up the lap words. The 12" side lap may hit the stud bay, and not the stud. The paper could fall/fold into the space before insulation, that's why I said next stud back.

The very best way is rain screen of installation:

http://www.greenhomebuilding.com/pdf/RainScreen.pdf

Suobs, do not rely on caulking alone to weatherproof the siding. Over the windows and doors, install z - flashing, top edge tucked under the paper. Different thicknesses are availiable for different trims over the units, and over the head trims.

Caulk all fasteners, setting them snug but not breaking the wood's surface.Do not nail the overlap side through the previous underlap sheet. Nail slightly next to it.
Pre-prime the siding, all 4 sides, for a premium installation, painting the cut edges also. Sorry to confuse at times. Be safe, G

 

Thanks for you help and I see we're on the same page - a premium installation! I've seen plenty of rot on the previous work.

Yes, z-flashing at any horizontal joints and above windows/doors, and priming all 4 sides of the T1-11.

Not sure what you mean by caulking fasteners. This is on the siding or the paper, and how would I do this?

Also, you say "nail" - I was planning on staples for the paper. No?

I also don't get the part about "don't nail the overlap side through the previous underlap sheet". You're saying to only fasten through one sheet of felt at a time?

To make sure I have the overlap right: from bottom to top (I think of as horizontal because the overlapped edge is horizontal) it should be 3". If I finish a roll and need to overlap side to side (vertical edge), it should be to the next stud back.

 

Not sure what you mean by caulking fasteners. This is on the siding or the paper, and how would I do this? I was referring to the siding nailing.

Also, you say "nail" - I was planning on staples for the paper. No? Again, the siding.

I also don't get the part about "don't nail the overlap side through the previous underlap sheet". You're saying to only fasten through one sheet of felt at a time?Again, the siding.

Correct, staple the paper. Your other post on bevel the drip-edge is a good idea, just be sure to seal it. Be safe, G

 

Thanks for the rainwall suggestion - I might try it if I can.

Any thoughts on using these vents under plywood siding (the vertical furring would be over the builder paper and nailed on each stud)?

I can get the Cor-A-Vent shipped from the company but the main hangup is, of all things, finding z-flashing for a 1" siding application because of the extra half inch for the furring and vents.

Any suggestions for where I can get z-flashing online in this size?

 

Second from the bottom: Cor-A-Vent : Ventilation Products

Where is the flashing going? Be safe, G

 

OK sorry. To clarify, all of Cor-A-Vent's diagrams show an installation under an overhang. On my gable ends I have cedar lap siding down to the double top plate above the studs, then there will be the new T1-11 over the new studs down to the curb. The z-flashing goes over the top of the plywood where it meets the lap siding at the bottom of the gable end.

The lap siding is part of the existing polebarn carport, open on both long sides (40 ft) and closed at the ends (20 ft) until I took those walls (not structural) down to rebuild them. The framing I'm doing is to fully enclose the structure. The previous (seriously rotted) walls at both ends had existing z-flashing below the lap siding and covering the top of the previous siding. It is still there and I thought I would re-use it until the rainwall idea came up.

The only problem I see with using the siding vents is the extra half-inch of projection from the studs (because of the vents and furring over the studs). This means that with the vents the plywood part of the wall will project about out 1/2" further than the lap siding. This might look wierd until I adjust the gable ends next year, but my main concern right now is the integrity of the new siding.

MY QUESTIONS ARE:

(1) Does this installation make sense? Will the siding vents improve the installation of T1-11 plywood, primed all sides? Is it worth the trouble?

(2) If I go with it, the only way I can think of to protect the top of the siding is to replace the existing z-flashing with z-flashing that extends out another half inch. But I can't find it, even online.

(3) Does having the siding project out below the lap siding make sense or will it cause problems, even with z-flashing?

 

I don't think your application of the rain screen would work. I would replace the siding with T-1-11, and felt paper, priming as I said, bevel cutting as you said. Caulk the nail heads after installation. Be safe, G

 

Thanks! I appreciate your interest. I'll follow your recommendations. Maybe I'll let you know in 10 years how it worked!

 

You are welcome. I'll be 71 then, so use bigger font. LOL. Be safe, G

 

A couple more now that we're in progress with the felt.

Should the felt seams be taped?

Should staples be caulked?

 

Should the felt seams be taped? Nope.

Should staples be caulked? Nope. Be safe, G