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Rim Joist and floor joists rot (pic heavy).

Posted by kwerk (My Page) on
Tue, Aug 31, 10 at 12:37

I pulled the deck off my house and found some rot and other problems.

Roughly how much should it cost to repair this wood damage, and how do you think should be done? This is a two story wall above.


Rotted floor joist and sill plate. This is the only rotted part of the sill plate, how long a section of sill plate should be replaced? Just under this joist or span 2 or more?

Broken joist end. Should this be sistered?

There are a couple joists that are "sunken" about 1/8" in to the sill plate. The wood still looks/feels good. I'm not sure if it was caused by moisture or if it's normal. Is this a concern?


The circles indicate rot. The line at the bottom is where the rim joist seems to have been pulled out 3/4" at the top by the old deck which was pulling away from the house. The old deck ledger was simply nailed on.

Rim joist not plumb with rest of framing:

About 1/2" gap from the joist end at the top:

Close up of water damage, notice the sub-floor does not go all the way out to be flush with sole plate and rim joist?? :

My plan:

1. Get wood fixed.
2. Replace the removed foam sheathing with Huber Zip or regular OSB and tape to foam with Vycor flashing.
3. Remove doors, flash sills with Vycor, reinstall doors.
3. Apply Grace Vycor on OSB behind the new deck ledger and.
4. Attach 2x8 deck ledger with Ledgerlock screws.
5. Apply Grace deck protect over the ledger and some rigid ledger flashing on top of that.
6. Attach some cedar board where the siding was removed (old composite siding damaged beyond reuse).

This way it should be easy to reside the rest of the wall in a few years and blend it in to the deck flashing.

Follow-Up Postings:

RE: Rim Joist and floor joists rot (pic heavy).

I just measured how much the rim joist is out of plumb from the sole plate and it is only 1/3", not 3/4".

RE: Rim Joist and floor joists rot (pic heavy).

I would just replace the amount of sill plate that is actually bad, maybe just a couple of inches past the bad area.

I wouldn't worry about the little broken piece on the joist end or about the joist stopping 1/2" shy of the rim joist. I don't think the joist sinking an 1/8" is a major concern, although a bit odd.

I wouldn't use the adhesive flashing anywhere that requires the adhesive to work. Such as taping the foam to the OSB, if the adhesive fails it will funnel water onto to the OSB. I would use housewrap or similar material and run it 6" up and behind the foam. Then, out and over the OSB until it reaches the rigid flashing.

RE: Rim Joist and floor joists rot (pic heavy).

Flashing is your friend, eh?

For your new ledger, investigate/Google Maine Deck cleats. Another poster (sorry, forget who) gave a link a few days ago).

Up here we use an injection molded "puck" for the very same thing. It sets your ledger off the wall, making very small (and easy) areas to render watertight. Air circulation, drainage and ease of install. Win, win. Win.

RE: Rim Joist and floor joists rot (pic heavy).

Fungus feeds on the sellulose in wood and makes it too soft for structural support. Use an ice pick to determine where that has happened so you can remove the soft wood and replace it.

Attaching a deck ledger to a house is an invitation to trouble no matter how it is flashed. Water needs to be able to pass between the house and the deck.

Here is a link that might be useful: aluminum brackets

RE: Rim Joist and floor joists rot (pic heavy).

It appears to be solid and structurally sound. I would close it back up.


I would be concerned how much the floor is out of level and if that has compromised the operation of any doors. You might need to take the load off of the framing in order to repair/replace the damaged portions.

It is wise to use Grace water based primer (WB Primer) behind any Vycor adhered directly to sheathing (especially OSB) if you don't want water to get behind it. Unfortunately, it is usually sold in 5 gallon containers.

Tyvek HomeWrap is pretty watertight (unlike most other housewraps) but it is not very abrasion resistant so I would not use it or any vinyl product as flashing.

Avoid the use of unfinished aluminum sheet flashing against pressure treated wood or anywhere else where it will be in constant contact with water.

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