# how to fix rotted sill plate



## carole2cd (Mar 13, 2007)

while replacing siding , we found the sill plate rotted from water damage. how can I replace it? its on one side of an old add on laundry room about 5 feet in length. also the corner wall stud also has rot.


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## redline (Mar 5, 2006)

Is thi sitting on the ground or is it on a foundation?


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## carole2cd (Mar 13, 2007)

on the concrete foundation


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## redline (Mar 5, 2006)

One story structure or two?


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## carole2cd (Mar 13, 2007)

one story


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## AtlanticWBConst. (May 12, 2006)

carole2cd said:


> while replacing siding , we found the sill plate rotted from water damage. how can I replace it? its on one side of an old add on laundry room about 5 feet in length. also the corner wall stud also has rot.


Carol, 

Check to see if the rotted area has allowed any sagging of the floor joists that sit on the rotted plates. If it looks ok;

What you would do is start on the inside to do this repair. First off, is the interior area on the inside of this mud sill plate finished (sheetrock attached to the plate)? If so, you would have to remove the interior materials(Sheetrock and insulation) that are attached or near to the areas to be replaced.

Inside - You would build a temporary framed wall using 2x4's with a top plate and a bottom plate. Something like this:










You would only need to build one wall that is about 2 feet longer on each end than the area it is that you are going to replace. It has to be a snug fit. You may wish to place a scrap piece of carpeting on the top plate, so as not to damage the ceiling.

This temp. wall is going to support the flooring joists and any weight that they are holding. (Those floor joists are sitting on the mud sill plate that you plan to remove and replace)

Once this is done, you can start the work on the outside. You will have to obtain a reciprocating saw (Sawz-all) if you do not have one. Using a metal cutting blade, cut the nails at the bottom ends of the studs (that are nailed into the mud sill plate and wall plate) Cut these out along the rotted area that is to be replaced. 

Once this is done, use a wood blade in the reciprocating saw to cut a straight line down and cut out the rotted plates (both layers).

Remove these with a heavy hammer, small sledge, large chisel, pry bar....what ever is the best tool for the process.
Clean up the area well. 

Replace these with Pressure Treated lumber. You may use KD grade stock for the wall plate and Pressure Treated stock for the mud sill. (MAKE SURE: that you try and find a dry/seasoned length of PT stock, if it is still moist, it can be swelled as much as 3/16" wider in thickness than what was originally serving as the plate. This would be a little difficult to install)

You may have to 'muscle these in. If you do run into measurement/thickness issues, you can cut a little off the studs (1/8") to fit the plates in, then shim the stud bottoms snug - and toe-nail into the plates. (You could cut the studs using a wood blade and the reciprocating saw)

Use galvanized spikes to toe-nail the new PT mud sill plate ends into the existing mud sill plates... When nailing, making sure to sink the heads even or below that plate's surface. Then install and nail the next KD plate (the replacemant for the lower wall plate)

Also: If there are any foundation anchor bolts in the area; cut a slot in the new plates on one side....(like a 'U' shape) in order to slide the replacement PT stock into the sill area. You may even be able to re-bolt these from the inside with some large washers. If you can't -don't worry about it.

Last: Remove the temp. wall. Install new insulatation and any other materials that were removed during the repair process. Close up the interior area and the exterior with new materials...

Be sure that you did find and repair the causes of the rot (to begin with) - so that this does not happen again. It may be poor drainage, roof issues, leaking window or door, removing plants, etc..etc...

Good Luck.

(FWIW: Last time we did a repair like this was also on the corner of a house. Two stories and the home's corner had dropped from the rot)


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## TSchlosser (Mar 26, 2011)

What did you do differently to fix the 2 story house with corner rot? I discovered this situation on my home today when I pulled the siding back for an addition we are starting. The home is 1780's, the sill plate is actually a 6"X8" timber on a stone foundation with 12" rot in from the corner in both directions.


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## oh'mike (Sep 18, 2009)

Tschlosser----Start a new thread-----post pictures if you can--this sounds like a unique situation and will get better attention on its own.-----Mike----


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