Expert: Bruce E. Johnson - 2/12/2009

Question
QUESTION: Hi Bruce - question about flashing and attaching a ledger board.  I'm planning to add a front porch to my home this Spring and plan to make it a shed style roof extending over the front door of the house.  Rough measurements are about 14'L (left to right facing house), 7' deep(sticking out from house)with about a 4/12 angle.  My plan is to bolt a ledger directly through the mortar joints, supporting it on posts (6x6) at each end for load bearing since the brick veneer won't carry the load.  Question 1:  when attaching the ledger board to the home, would lag screws every 16 OC work to keep it tight against the brick as long as I have the posts carrying the weight?  Question 2 (multi-part):  When flashing the joint at the roof top and brick wall, what's the best method?  Do I really need to cut out the mortar joint with a diamond blade and tuck the counter flashing into it and then re-cement it?  Also for the flashing on the ledger board, is Z style right?  What kind of metal would you recommend for the ledger flashing if I use pressure treated wood? And lastly do I need to have end dams in the flashing? Thanks Bruce!

John


ANSWER: Hi John, If your wall is wood frame with brick veneer it is always best to find the studs of the wall and use a long enough lag bolt to penetrate the stud at leas an inch and a half.  Otherwise you may loosen the veneer and the roof section may try to pull away from the building during a wind storm.

As far as flashing goes: Yes I recommend cutting a reglet in the brick or mortar joint at least a half inch deep and have a flashing made to fit into that reglet (saw cut).  I don't use mortar to seal it however.  I use a urethane caulk such as Vulcum or Eucolastic (whatever is available in your area). Some people use bull or mastic which is tar based. I put caulking in the joint and then press the flashing into it and then add a top bead of caulking to seal the deal. I seal the ends with caulking or mastic.

If you have a sheet metal company available in your area or a company that does metal roofing you can get custom flashing made for this.  It will have a half inch lip at the top to fit into the reglet.  Then it will have a 90 degree joint to a vertical leg of 3-4" (some codes require 8") down to the top of your roofing and then a 4/12 pitch of 8-12" over the top of your felt paper. Then roof up and over the flashing and seal the top edge with bull or mastic.

 There are other methods available: you can just do a vertical flash against the brick without the reglet and bull or mastic the crap out of it, there is also a two piece flashing which you can discuss with the sheet metal people which involves a receiver piece that the flashing slips under and locks into place.

 I use .050 aluminum for this kind of work, it's a little more expensive but lasts a long time and outperforms galvanized flashing by many years.  I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com


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QUESTION: Thanks Bruce!  That helps out.  Guess I'll break out the diamond blade.  I'll have to find someone to bend me some metal in the right shape.  Gotta be a place around here (Cincinnati) somewhere.  

As for attaching the ledger board through the brick veneer into the studs...do you have any tricks/tips for locating the studs?  I doubt a stud finder will work through a brick wall.  If I had to, I could cut out the dryall below the upstairs window on the inside, that's directly over the front door and see if I can see the studs, but if there's an easier way let me know.  

One followup on the flashing...so I attach the flashing into the reglet and then down over the roofing felt.  So how then would I attach the top row of shingles?  You don't nail through the flashing do you?  Also, if the flashing is directly on the felt, wouldn't that allow water to get underneath the shingles?  Would it be better to lay the flashing on top of the top row of shingles?  Thanks again Bruce,

John


ANSWER: HI again John, you can use a stud finder inside the house to locate your studs and then use a point of reference on the outside to determine where the studs can me located on the outside.  In other words if you locate an interior stud that is six inches from a window or doorway you can use the window or doorway as your reference point on the exterior to measure from.  Stud finders aren't expensive and some can even locate studs through stone or brick using a form of radar.  Check with your local building supply store.  They come in handy around the house for other things as well.   Yes you can flash on top of the roofing but you need to flash under it as well.  That is why I mentioned a two piece flashing.  The first piece goes up the wall and under the roofing the second piece snaps up under the receiver after the roofing is done and caps the roof edge at this point to give you double protection.  You can also flash over the roof and then mastic a row of shingle on top of the flashing to hide it.  If you look at my original email you use a good coat of roofing tar or mastic to bed the shingles over the top of the flashing and then seal that joint with a good bead of bull or flashing mastic.

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QUESTION: Bruce - thanks again so much.  I assume that I'll need to pull a permit with the county for this kind of reno.  How will I be able to prove I've bolted the ledger into the studs/band joist without removing the dryall on the inside for inspection?  As for the flashing, I get it now.  I'll cut the reglet and tuck in the lip of the first layer of flashing and then tuck another piece up under it and down on the roof and then tar/silicone the crap out of it.  I appreciate your willingness to help me out.

John


Answer
Hi again John, I guess you will have to go through the motions of finding the studs inside and marking them somehow, maybe a strip of tape or something that won't have to be painted over.  Or a pencil mark if you don't mind doing some touchup later.  Then when the inspector comes out you show him how you determined where the studs were and show him how long of a lag bolt you used, etc.  Now I personally wouldn't bring it up unless he does.  Most inspectors are pretty hip to how things work plus, unless you hit the stud with your lag bolt your ledger won't be very secure.. I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com