Screened Porch (New Roofing)

[aka Larry]

First off let me say I don't know much about roofing. I have built ONE lean to on the back of my shop using corrugated metal and that's it. I have no experience with shingles or any other roofing.

OK, now that you know I'm a roofing noob, I need some help. The backstory is last last year my wife had a pair of jack legs to build a new screened porch off the back of our house. Though I'm no expert, it's easy to see that they wanted to do it fast, not do it right. The underside of the roof was enclosed with 1/4" plywood and now it's clear it's leaking because the stains in the white paint are very evident. I have since been told that "duh" no wonder it's leaking because the roof has something like a 1/12 pitch! Seems I've read somewhere since that something like 4/12 is the minimum slope for using asphalt shingles?

So moving forward I'm considering installing a metal roof over the existing shingles. This is not a large area at something like 8'x12', which is a rough guess. First I'd like to know should this be done with or without furring strips? Second what should the connection look like between the new and existing roof? When they built the roof for the new porch, they simply attached 2x4s to the house soffit. Another issue is the PVC ****** gutter that doesn't seem to catch the water hardly at all.

Depending on the recommendations from my fellow GJ members, I plan on fixing this disaster myself. The reason I didn't do it in the first place was because my wife has NO patience. When she wants something done, she wants it RIGHT NOW. Usually this is in June, July, or August, which is no time to be on a roof here in NC if you can avoid it. Now the cooler weather is here, I should be able to get it fixed.

I'm open for all thoughts and suggestions right now with the limited info I have given, though I plan to take pics soon so we can dive in the details with better information.

Thanks!

 

[Falcon67]

Because of the leaks, IMHO I would remove the existing shingles. A 10x10 area of shingles weights 220~250 lbs so if the roof is built from 2x4s getting that weight off would be a real good idea. Then repair/replace any damaged decking to insure a solid surface. I'd then cover it with stick down underlayment and put my metal over that. Not sure about the stand offs - that's probably a condensation related question, although that could depend on the type of metal. Corrugated tin would allow for drainage where another type maybe not.

The best low slope roof repair I've seen was one done on our old house back porch. Very low slope, 2x4 construction, deck about 18x16 in area with 1/2" ply over/under. The roofer recommended hot mop with roll roofing over the deck. That was in 1999 and that patio roof is still in great condition.

 

[oldmxracer]

The shingles need to come off !

It is only 8x12.

I would old school epdm glue down It would be one piece of rubber !

Your tie ins (flashing to the house) would have to see pictures of what You have going on ?

Just My thoughts !

 

[aka Larry]

Thanks for the input so far guys.

I need to get some pictures to give everyone a better understanding of what I'm dealing with.

I heard of the stick down underlayment, but have not seen it in person. Got a link to the product at Lowes or HD?

 

[Bretny]

EPDM rubber roof is what i would also use. You can buy a sheet to cover 8x12ft at most big box stores.

Most metal roofs are rated for a pitch down to 3/12...the same 3/12 that shingles need.

They do make a metal pannel thats rated to 1.5/12 pitch its called a PBR pannel. Good luck finding it in such small quantity as your going to need.

 

[aka Larry]

EPDM rubber roof is what i would also use. You can buy a sheet to cover 8x12ft at most big box stores.

Got a link?

Sorry, I'm such a total roof noob all this is new to me.

 

[oldmxracer]

Would need pictures for Your flashing details and good measurements.

Here might be close to a full kit of most of what You might need.

https://www.amazon.com/dp/B00WIR1GII/?tag=atomicindus08-20

 

[matt_i]

A good ice+water shield like Grace should mitigate the leaks. It has the advantage of being able to still use nails as it seals the shanks. For that reason I'd use true hot dipped galvanized nails and not the electroplated ones. Just hand drive them for the small area.

It would be worthwhile to frame up to around 3:12 pitch imo and apply min 1/2" CDX but I don't know how hard that would be.

 

[HotrodHR]

Need pics... but from your description it sounds like you have more problems waiting to happen... tie in to soffit for starters.

 

[Bretny]

Got a link?

Sorry, I'm such a total roof noob all this is new to me.

Type epdm roof into anybsearch engine.

 

[aka Larry]

I'll try and get pics this weekend. Been really busy this week and haven't gotten home in time to get pics before dark.

 

[bradpac]

Pictures would be helpful. If there's not a lot of water dumping on it from the other roof, with that small of area the biggest issue will be the flashing to protect against windblown stuff, unless you're dumping a lot on to it.

 

[ddawg16]

Home Depot has the lay down stuff if you want to go that route.

I went to a roofing store and picked up some better stuff....it comes in two parts....one is an adhesive underlayment........then the actual roof material....you peal off the protective layer and stick it on....with 2 people....it's easy.

If you go metal....you can order the panels in the length you want. If you already have shingles, then it's obvious you have plywood below them. Remove the shingles...repair any damage....I personally would prime and paint it for future proofing....then toss the steel on top. Make sure you do the top flashing properly to prevent any water from getting in between the house and steel.

Here is a pic of my patio

 

[aka Larry]

If you go metal....you can order the panels in the length you want. If you already have shingles, then it's obvious you have plywood below them. Remove the shingles...repair any damage....I personally would prime and paint it for future proofing....then toss the steel on top. Make sure you do the top flashing properly to prevent any water from getting in between the house and steel.

If I remove the shingles and tar paper (I think that's what it's called here) are you saying I can just lay the steel directly on the plywood with no underlayment?

Thanks for all the helpful replies so far!

 

[rburke65]

For that size of a porch....small.....I would cover it all with a Ice n Snow guard, then do your metal using screws. The sticky under later will help seal the screw holes as well as the neoprene washers under the screws head......in my opinion.

 

[ddawg16]

If I remove the shingles and tar paper (I think that's what it's called here) are you saying I can just lay the steel directly on the plywood with no underlayment?

Thanks for all the helpful replies so far!

Pretty much. Like I said above...I'd prime and paint it first. Get all the edges....reduces the chance termites can get in.

I've started doing that will all external wood. I prime it first....even the hidden edges....then put it together...and then paint. The primer makes it more difficult for termites to get into your wood.

But it wouldn't hurt anything to toss down some 15lb tar paper...it's cheap enough.

Just make sure you use the right screws for the sheet metal...it must have the rubber washer....otherwise, water will leak in.

 

[Dave in Mass]

Let your wife know that if you say you are going to do soemthing, you will.

She doesn't have to nag you every 6 months about it

Like others, I would focus on how this is tied to the house and make sure tehre is proper flashing.

 

[matt_i]

If I remove the shingles and tar paper (I think that's what it's called here) are you saying I can just lay the steel directly on the plywood with no underlayment?

Thanks for all the helpful replies so far!

One can also use the ice + water under the metal roof.

Grace makes a high temperature version for just such applications....apparently there were fails from the normal ice+water under the hot metal of the roof.

Its labeled with the -HT (high temp) suffix appropriately

If there are roof edges that terminate on a wall, then my free advice is to google, understand, and install kickout flashings. Those are one of the most -missed details in flashing. The other ones are roofers' aversion to touching anything to do with siding and making compromises in other flashing areas. If a person owns the "whole job" they will do it differently.

 

[aka Larry]

OK, time to revisit this.

The wife couldn't wait for me to fix it, so she hired yet another guy when I was out of toen who didn't know WTF he was doing. I could have paid to fly one of you guys here and still come out ahead on this PITA project.

After the #2 guy "fixed it" it still leaks like a mofo. It's been winter and we aren't using the screened porch at that time of the year so I've been ignoring it. Fast forward to now, spring is coming and the wife wants it fixed.

Yesterday I finally climbed my *** up there to take a look and see if I could see WTF was the problem. First off, as stated earlier it's f*cking flat. Well, it's not technically level, but not far from it.

From what I can tell the #2 guy tore off the shingles and roofing paper, replaced the water damaged OSB, and installed the metal roofing. To transition from the shingles to the metal, he slid a section of flashing under the second shingle, added some tar, and simply used roofing nails to attach it to the metal roofing panels.

My layman's opinion is the above method, while looks ******, would have worked on a roof with enough slope because water likes to go downhill. However, it appears with the roof being flat, the water backs up under the flashing he added and travels down the face of the soffit. I say "appears" because the 2nd guy tore down the 1/4" plywood interior and replaced it BEFORE he waited to be sure the roof above was not leaking. I have't torn the interior plywood down yet, but I will, and we will replace it with PVC like the soffit already on the house AFTER I know the roof doesn't leak!

Take a look at the attached pics and let me know what you think I should do. Remember I'm a roofing noob as the only one I've built is a lean-to off the back of my shop, but guess what? It's also metal, has a 12/3 pitch, and it doesn't leak!

Please be detailed and provide pics and links if you can.

 

[Bigbandguy]

We went through this earlier this year. Same 1/12 pitch, same problem except it had been leaking longer. We tried the new shingles, etc. It came to a head when we were having the inside of the porch faced with tongue and groove spruce and the leaks HAD to stop. New roofer tore everything off, installed a rubber membrane roof, THEN put on shingles just for appearance and to match the house. Does not leak a drop now. The porch has two skylights and it was leaking around those as well as on the edge where it joined the house. It was worth the hassle and turned out ok. Gook luck!

 

[ordpete944]

I have a 1/12 pitch porch roof on the front of my house. I used the two layer roll roofing and ran that up under the shingle of the house a good 2 feet. Smooth transition from shingle to roll roofing. 4 years and no leaks.

 

[Dustball]

You never mentioned there was a valley involved. That throws a wrench into the works. You're going to have to pull off the plywood to see exactly where the water is coming from.

Also, it looks like your shingles have too much exposure. https://inspectapedia.com/roof/Shingle_Exposure_Standards.php

 

[ddawg16]

OK, time to revisit this.

The wife couldn't wait for me to fix it, so she hired yet another guy when I was out of toen who didn't know WTF he was doing. I could have paid to fly one of you guys here and still come out ahead on this PITA project.

After the #2 guy "fixed it" it still leaks like a mofo. It's been winter and we aren't using the screened porch at that time of the year so I've been ignoring it. Fast forward to now, spring is coming and the wife wants it fixed.

Yesterday I finally climbed my *** up there to take a look and see if I could see WTF was the problem. First off, as stated earlier it's f*cking flat. Well, it's not technically level, but not far from it.

From what I can tell the #2 guy tore off the shingles and roofing paper, replaced the water damaged OSB, and installed the metal roofing. To transition from the shingles to the metal, he slid a section of flashing under the second shingle, added some tar, and simply used roofing nails to attach it to the metal roofing panels.

My layman's opinion is the above method, while looks ******, would have worked on a roof with enough slope because water likes to go downhill. However, it appears with the roof being flat, the water backs up under the flashing he added and travels down the face of the soffit. I say "appears" because the 2nd guy tore down the 1/4" plywood interior and replaced it BEFORE he waited to be sure the roof above was not leaking. I have't torn the interior plywood down yet, but I will, and we will replace it with PVC like the soffit already on the house AFTER I know the roof doesn't leak!

Take a look at the attached pics and let me know what you think I should do. Remember I'm a roofing noob as the only one I've built is a lean-to off the back of my shop, but guess what? It's also metal, has a 12/3 pitch, and it doesn't leak!

Please be detailed and provide pics and links if you can.

Problem #1.....your original roof is installed wrong. See all that black at the top of each shingle where it touches the one above it? That is your tar....that is supposed to be UNDER the shingle above it. When the roof is first installed, after a few days the heat of the sun melts that tar and it helps to bond the shingles together....reduces the chances of wind blowing them off. IMO....the roofer who did your roof was trying to make the shingles go further so he spaced them out more than he should have.

Because the shingle above is not on that tar....it can lift up....additionally, it's easier for water to blow under the shingle.

Problem #2. With the low slope, it's too easy for water to push up under that metal flashing.

Problem #3.....See your valley where the two roofs meet? Water comes down that valley at a pretty good clip and will rush under your flashing

Problem #4.....no valley flashing. But I'm not surprised. Using shingles in the valley is the cheap way to shingle. That is also one of the first parts to start to leak. It sees the most erosion of roofing material....and given improper install on the shingles, you are more likely to have water push up under the shingles.

Problem #5....he used roofing nails on the metal instead of rubber gasket screws.

Larry.......that is one fucked up roof.

 

[Joemctag]

Assuming the metal roof screws and laps are done correctly, your assessment is probably correct that water is getting blown up the metal sheets. Would have been better black or white membrane. They’d run it up with he said dieting roof a foot or so, so there would lent be water getting blown under the overlapping existing shingles. You can leave the metal roofing an use much wider flashing on the uphill side to stop the water-blowing problem. It looks like the right-hand side might be ok.

 

[CN Spots]

I'm no roofer either but that dark stripe is pretty common on architectural shingles. It's supposed to resemble a shadow and make the shingles look more thick. If you google architectural shingles, a lot of them look like that.

Here a similar one from Home Depot:
https://www.homedepot.com/p/Owens-C...Shingles-32-8-sq-ft-per-Bundle-HK20/205655917

 

[yeldogt]

It's hard to tell if the shingles are installed correctly -- most I have done hide the top tab curve. You would have to look -- if so the head lap is off.

The whole metal roof is wrong .. when you make any kind of transition to metal it must be made correctly .. there is a cap that has to be made -- it's all set back to stop any water from backing up ... it's then taken back into the other roof.

Also -- anytime you see caulk -- be warned. It always fails.

This is my newest metal roof -- see the cap. It's deceiving because I'm on the ground and the angle -- it's a steep roof -- the cap has upwards of a foot of run. It's the same detail if the upper roof had been shingle

 

[Hooked]

There is another possible problem with the metal roofing. I don't see any screws in the ridge of the overlap seam. Also, if there's no screws on those seams, I'm betting there's no caulk tape on those seams either. Thus, another possibility for blown water intrusion.

I think you're better off to remove the metal and put down one of the rubber roofing materials. I'm not familiar with the ice/water stuff or the EPDM sheets but my daughter just had TPO roofing put down on her (almost) flat roofed screened porch. We have been fighting leaks on that roof for several years due to shoddy work the original owner had done.
Good luck with whichever option you choose.

 

[oldmxracer]

Will stick with what I suggested in post #3 old school, glue down EPDM. Installed properly You will have NO LEAKS !

You do not have a complicated roof, just a low slope roof with the wrong materials installed.

In post #7 this might be most of everything You need, would still need more measurements and pictures.
https://www.amazon.com/dp/B00WIR1GII/?tag=atomicindus08-20

 

[ddawg16]

I'm no roofer either but that dark stripe is pretty common on architectural shingles. It's supposed to resemble a shadow and make the shingles look more thick. If you google architectural shingles, a lot of them look like that.

Here a similar one from Home Depot:
https://www.homedepot.com/p/Owens-C...Shingles-32-8-sq-ft-per-Bundle-HK20/205655917

Hmmm....you might be right.....but it sure looks dark....this is what mine look like.....not nearly as pronounced....at that roof at the time of this pic is about 10 years old

 

[aka Larry]

Final update on this!

I hired an actual ROOFER (vs. the two jack-leg ones my wife hired) to come and fix this damn thing. He removed the water logged OSB, and replaced with 3/4" plywood per my request. Next he installed a layer of hardboard-type insulation and covered the entire thing with a rubber membrane that ties in to the existing roof about three rows of shingles up. He installed a 6" gutter and downspout that is piped out from under the deck. Charged me $1400 for everything.

After he was done, I replaced the water logged 1/4" plywood ceiling with vinyl soffit material, added 3 LED lights and 2 ceiling fans.

The roof hasn't leaked a drop and we've gotten a lot use out of the porch since.

 

[nadogail]

Very informative thread.

 

[LS6 Tommy]

Problem #1.....your original roof is installed wrong. See all that black at the top of each shingle where it touches the one above it? That is your tar....that is supposed to be UNDER the shingle above it.
Larry.......that is one fucked up roof.

I'm no roofer either but that dark stripe is pretty common on architectural shingles. It's supposed to resemble a shadow and make the shingles look more thick. If you google architectural shingles, a lot of them look like that.

Here a similar one from Home Depot:
https://www.homedepot.com/p/Owens-C...Shingles-32-8-sq-ft-per-Bundle-HK20/205655917

Yup. The "shadow" is very common. Glad you got it fixed right. akaLarry.

Tommy