Roofing felt, vertical or horizontal

[suburbancowboy]

I am wondering if anybody has ever put there roofing felt on vertically instead of horizontally.  Reason I am thinking of this is because I have a 12/12 pitch roof on 12 foot walls.  I am thinking I can pre-cut the paper and go lay it on both sides at once and put on the metal roofing all at the same time then move back and do the next row.  I would still over lap the felt but the seam would run vertical.  Does anybody see an down side to doing it this way?

[Redoverfarm]

Several have done it vertically.  It is designed to go horizontally so that the water will fall with gravity and not get under the seams.  How much water will or could enter vertical your guess is as good as mine but with horizontal probably none.

On an added note if you will be some time between roof felt and metal or shingles might I suggest Titanium Felt underlayment.  It will last longer that Felt and hold up better.  A little costly but "if" you are going to be 2-3 months between stages a worth while investment.

[Don_P]

I'll raise my hand, but vertically is incorrect, code specifies horizontally and lapped shingle fashion.

[mldrenen]

as an aside, if your roofing felt comes with horizontal guidelines, don't use them.  they aren't straight.  i just finished felting my roof over the weekend, and had a heck of a time trying to lay row after row using those lines as a guide, and couldn't figure out why the felt kept bunching up.  then i measured the lines and found them not perfectly parallel to the end of the roll.

are you planning to use staples or nails with plastic caps?  i think local code requires the nails w/ caps here, so that's what i went with.  it sure would've been much easier with a slap stapler, though.

[suburbancowboy]

I have both nails and staples. In the past I have always gone horizontal but this is a lot steeper and larger project.  Once the metal roof is on does the felt really make much of a difference?

[Redoverfarm]

As the saying goes " It all depends".  Meaning that the proper way to insure the felt does not blow is the time span of installation of the felt and when you put the metal /shingles on.  If code is permitting you could use staples if you are going to immediately install the final roof.  But if not I would nail with caps.  The felt will pull and buldge with exposure to the elements.  Staples will just not hold if left exposed for any length of time.  Even with button nails the felt will become destorted but it is better than staples.   As my earlier post mentioned Synthetic felt which when installed correctly will not move and stays flatter.  

My roof was a 10/12 and with the use of "roof jacks" I installed the underlayment from the top down leaving the bottom edge loose and then inserting the next row under it until I reached the bottom (eve) edge and finished with a ladder.  

If you do not have access to lifts to help you install your metal you might check on making a "chicken ladder" which will allow you to work from one end to the other installing your metal and moving it as you progress to the other end.  Still takes at least two-three people to put it up ( one ground , one ladder and one straddling the ridge).  

[Native_NM]

The consideration besides code is insurance.  If you were to insure your place and something were to happen that removed the roofing, exposing the paper, and you were to suffer water damage, a smart adjuster could deny the claim.  Happens all the time.  The paper is the weather barrier.  Metal does not generally have the same issues as shingles, but it short dollars to do it the right way now.  Just my $0.06234 cents.  (<< inflation adjusted)

[suburbancowboy]

Well the verdict is in.  We put the first row of stick felt on the roof horizontal.  Because of how high the roof is it took about an hour to get it on.  What a pain, so I changed plans and put the rest of the felt on vertically with 1 inch over lap on the seams.  That was so much easier.  We would set the ladders, put on a row of felt and then a row of  metal.  I figure that this saved us about 3 hours.

[MountainDon]

An inch overlap is a tad short, IMO, not to mention that the method does not meet code. 

Note: the usual method of overlapping roofing felt is:
[1] horizontal laps, 2 inches minimum
[2] vertical laps, as in where one horizontal run of felt stops and another starts, 4 inches minimum and 6 inch overlaps on hips and ridges.


Difficulties with installing metal roofing (not wanting to fall off the roof) was why I hired someone for that part, though I did all the felt. .

[Don_P]

Don't know if I've ever mentioned it but we usually try to install the bottom row of roof ply, lean out over it and run the bottom row of felt and bottom toeboard. Then the tough row is done, after the first row and up on toeboards it goes pretty quick.

[suburbancowboy]

I agree that it would have been better to go horizontal but the 12/12 pitch roof, the height of the roof and running out of funds to get things dried in I think that this was a good choice.  Thanks for the the feedback though.

[nathan.principe]

I also installed my felt vertically in the same fashion you did, by alternating the felt and metal panels.  I also have a 12/12 pitch and my cabin sits way high off the ground, not to mention a second floor!  I went against everybodys opinion ( which I do value) because there was just no way to do it properly in my eyes.  My understanding is that the main purpose of the felt is do shed condensation that forms under the metal, so I can imagine that much or any moisture would work its way around and under the felt to cause significant damage

[nysono]

going to run mine vertical too; steep roofs, old bones and smaller cahonies make variations of the norm necessary....

[firefox]

If you have to do it that way, I would suggest 12 inch overlaps
and use roofing cement to bond the sheets together. It is not
that much extra effort for what it buys you in peace of mind.
Dab a little over the nail heads while you are at it if you can.
Just my two cents,
Bruce