Roof sloping toward wall - how to prevent leak

Hi all experts:
I have a garage roof that is sloping toward a side wall of the main house. The roof of the main house is higher than the roof of the roof of the garage, and water flows from the garage roof toward the wall as shown with the arrows in the picture. This is a remodel and no roof has been installed yet. With the two storms that we had a few weeks ago, water was flowing down the wall of the main house. t is currently bare framing with plywood and no sheet rock. I am hoping for your suggestions as to what to do to redirect the water away from the wall toward the opening at the bottom (where the garage roof and the roof of the main house almost intersect.) I have looked at roof to wall flashing but I am not sure if that will do the trick and am hoping for more expert opinions.
thank you.

It looks like the walls can be flashed normally it is just a tight area.

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I would ice shield up the first 3 courses as well as the wall where that all comes together turning it up where you can, then flash as normal.

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Do you get snow and ice?

Thank you for your responses. Snow and ice are unlikely to happen often in this area. Regarding ice and water shield, do I install it along the edge of the wall where the garage roof meets the wall (i.e., perpendicular to the arrows shown in the picture)? Regarding flashing, what type of flashing would you recommend? Also, does it make any difference if the roof is going to be S tile roof? Thanks again.

Is the S tile gong to fit under the house overhang?

Roofing that as is will create a nightmare for the next guy. I would wall off the areas in red. Small saddle behind about where that guys foot is. Otherwise future repair or replacement will take alot more work.

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Sorry, the picture may not be clear, but the water also flows into the wall at the top portion of the garage roof (continue your red line upward from the guy’s right foot to above where the guy’s right hand is.) If I block that gap, it will be essentially from the ridge of the main house roof toward where your horizontal red line is. Regarding fitting the S tile, yes agree, it would be very tight. We may have to trim the fascia.

I would start by removing the overhanging plywood so that you can get in there and work comfortably. Next ice shield up the wall at least 1’ and onto roof 2’. A single piece run verically will work for this. Horizontal with laps is fine too, just make sure you build up from bottom up and dont have any reverse laps that will direct water to sheeting. Next step flash as usual making sure you have at least 2" overlap between flashings. 10’ lengths of L flashing with a hem with 8" of caulked overlap between pieces would also work for sidewall. I this would be more common than step flashing for the S-tile option, but can leak if not kept clean of debris. I would then do siding and paint before putting plywood back on upper roof. Use screws for plywood on upper roof and dont nail flashings to wall if you want to help out the next roofer. Also make sure the barge board is not touching the roof or it will rot.

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It absolutley matters that the roof covering will be a S tile roof.

If that is truly what your are going to use then the guys in the picture have absolutley no idea what they are doing.

For starters: the felt is the wrong kind, the felt 2-ply stagger is wrong (there is no 2-ply felt installation shown in this picture…that is one ply of the wrong felt paper), the step up rake where the guy in the black shirt is standing is architecturally unsound for an S tile and will be a booger bear to properly flash, the drip edge at the eaves was not installed prior to and under the felt paper and the felt paper was not turned down the outside rakes.


Thank you all for your comments. I am the home owner and your comments are helpful. What you see in the picture was essentially a quick fix to protect the plywood from the constant rain and several storms that we had this year. You can tell by the picture that it was overcast and the rain was coming that day.

Keepitlow: If I want to use the S tile, what do you suggest needs to be modified so that the flashing will not be a booger and provide me the best protection from leak?

1st things 1st:

Is the framing of your home structurally rated to take the weight of a tile roof? Are you using actualy clay “S” or are you calling extruded concrete tile “S tile?” Either way you, a standard weight tile roof will be +/- 900 lbs. per square dead load…before all of the accessory items and flashing techniques.

Did the architect and engineer of record provide for proper framing design and did the framer, in fact, build per the plans?

This question needs to be answered prior to going into the rest of the conversation if you want a tile roof.

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Yes, the roof is engineered and the engineer confirms that light weight tile roof can be used. I have already looked at clay roof samples from Boral and may go with the light weight Valejo style. These are S tiles. Roofing structure, sheating and nailings have been inspected and signed off by the city inspectors. Thanks.

As RooferOhio said, the step up rake / eave overhang needs to be eliminated. The soffit terminus under the overhanging eave will not provide enough clearance for flashing, tile or the ability to swing a hammer and drive a nail. That area should be furred out to complete delete / displace woeful overhang clearance.

The furr out will provide a new “wall” that can be flashing with tile pan which should slip under and into a receiver strip / drip edge above. The receiver strip / drip edge can then be “flashed” with the rake trim tiles installed at the upper level roof rake.

The problem I see is at the bottom of of this you will need to get the water exiting the tile pan drainage plane back on top of the tile prior to it exiting the roof at the eave where RooferOhio drew his bottom black arrow. That is going to require a rather large lead soaker sheet and while it may work it will be quite ugly. Again, bad architecture is the cause of this condition.

Make sure your roofing contractor knows what he is doing. Tile roofs are not shingle roofs.

Where is this job located?

Totally agree. Bad design on the roof.

Yes. I got many comments about the bad roof design :-). Dealing with the architect is another headache altogether that I do not wish to revisit. This is in California. Yes, that bottom area where everything intersects is looking quite ugly. In fact, I discussed with the framer recently about what he plans to do make it look more pleasing to the eyes. Thanks Keepitlow and everyone for your comments. The comments have been great.

I think the roofer thinks his 10 inch laps are two-ply. LOL.
It should be about 19 inches.

This is one of those jobs where if a customer Insisted on putting tile on that roof on it I would tell them to call someone else.


Already have two bids: 38K and 44K, one of which plans to do the same as Ohioroofer suggested. The picture shows the right side of the house. The left of the house is more typical. They estimate 45 to 50 squares. Is the price in the ball park for S tiles?

Personally I’m a believer that if it’s not done right to begin with then it’s going to be a forever problem there after
Not wanting to look for future grief and I wasn’t willing to correct a bad design I’d put a box gutter in along the wall.
There is going to be too much water running down that side from time to time