Hi All – I just bought a 100 year old Victorian in MA and have started tearing into it. The gorgeous, huge, wrap-around porch is in an advanced state of decay (primarily because of clogged gutters, and oh yeah, a 100 maple fell on it). I’ve transferred the roof load to temporary supports, so that I can replace … well, everything under it. The current fir decking runs perpendicular to the house, and is in reasonable shape close to the house (the opposite end, where the weather hits it, is in terrible shape) – it’s all coming off and getting replaced (after I replace the framing beneath … after I dig new footings …. arghhh).
My question: where the flooring meets the house now, it is tight up against the bottom layer of clapboards, with no evidence of flashing. I know this is wrong, but there is absolutely no evidence of a problem in this area (probably because the 10 foot overhang keeps it completely dry.) I don’t want to change for the sake of change, but I have an opportunity to lower the whole porch an inch, flash it correctly, and re-floor it. So should I, or should I just re-build exactly as it is? And if I do flash it, how is that done? I’m thinking of just using flat 12″ aluminum, tucked a few inches under the claps and against the house behind the new PT ledger – does this make sense. To further complicate, I should mention that there are a couple large curved bays enclosed by the porch, so I’m not dealing with simple flat surfaces.
Any advice would be greatly appreciated. Thanks, Bill.
Replies
With a ten-foot overhang, I'd be strongly tempted to not use flashing. As you noted, after a hundred years -- many without proper maintenance -- the ledger-end of the floor and framing is in good shape.
If you feel that yo need to flash, then you need to think like water. Flashing exists to prevent water from going where it should not go -- in this case, it is to prevent water from following the joint between the ledger and the house. The flashing must "start" above that joint, behind the siding.
From that point, it follows the sheathing to the top of the ledger board. It then follows the top of the ledger board (now going away from the house), then the face of the ledger board. You could think of it as a sort of stretched-out Z-shape (with the Z laid on it's back).
Any water that gets on the siding will drip onto the flashing, and will be directed away from the house.
Hi Bill.
Just your crazy neighbor passing by...
How is that end of the deck attached to the house now?
Is it just ledger boards nailed onto the sill?
My thinking is that so long as any water that blows in can fall through, and not get trapped behind the ledger, you will be set.
If you look at my house, for example, the sills were rotted where the ledger boards trapped water against the house, but I have no roof over my porch, as you know. Snow piles up against that wall, and water splashes back up under the siding. Adding the porch essentially 'raised the grade' in that area. You avoid all of this with that big roof.
The new ledger can be lagged (or bolted for overkill) into your big sills with a spacer block to hold it away from the house. If you wanted to be super paranoid, you could seal around the spacers, and flash over them from the water table down.
This assumes you are keeping those bottom trim boards and the water table in place.
Another alternative would be to set support posts near the house, and support the deck completely independent from the house. This might be the easier route with those curved bays. Difficult to set a ledger board on a curved surface. Also less likely to get in the way of any work you want to do on the house in that area (now, or in the future). Can set any deck height you like without worrying about meshing with the house structurallly. Zero water problems assured. The more I think about that design, the better it sounds.
Best of luck. I admire your tenacity. You can restore my house when you finish yours...
If the end touching the house appears ok, then from a preservation point of view it should be left alone. However if you do decide to lower the porch an inch like you said, I prefer to use continuous flashing and I space the ledger off the house a 1/2 inch by placing three or four stainless fenderwashers on the back of the lag bolts. This will give you a nice gap for water to drain. The flashing starts about 3 to 4 inches up behind the last clapboard and continues down to at least a 1/2 inch below the lowest point of sheathing.
Also this method is best of you are using aluminum flashing, because the new P.T. lumber specs say NOT to allow aluminum flashing to come into contact with the wood. (Unless you can still get CCA) Good Luck!
I don't understand! I cut it twice and it's still too short!
Edited 9/30/2003 11:15:09 AM ET by Manroot
If you decide to flash, and the floor system is to be PT lumber, don't use aluminum. Rather use galvanized steel, or copper. The chemicals in PT lumber accelerates the corrosion of the aluminum.