[r0ckstarr]

Two of my garage door jambs has some rot. The rot on each jamb is the right side of each garage door. The left side of each garage door is fine. Why did the right sides rot, but not the left?

Below is a picture of one of them. Someone tried to fix it once before, and as you can see in the picture, it has rotted there too.

Would you cut even further up above the rot and piece in new wood, or replace the entire board all together. I'm leaning towards replacing the whole board, but am open for suggestions on the right way to do it.

Also, should I use pressure treated wood, and if so, how long would it need to dry out before I could paint it?

 

[joecaption]

Main reason it rotted was because they installed it in direct contact with the concrete so water wicks up wood.
What to fix this once and for all?
Replace the wood with PVC lumber, or replace the rotted wood and leave it about 1/4 up off the slab and have it wrapped with coil stock.
Even the coil stock needs to be just off the slab so it does not buckle as that apron moves up and down with the seasons.
No way would I use pressure treated, it would take months to dry out enough to coat.

 

[FrodoOne]

Two of my garage door jambs has some rot. The rot on each jamb is the right side of each garage door. The left side of each garage door is fine. Why did the right sides rot, but not the left?

You asked "Why did the right sides rot, but not the left?" but my only answer can be "because that is where the water, which is causing the rot, is.

Firstly, remove (cut off) all rotten wood. Then remove, block up, eradicate the source of any such moisture. If you cannot prevent the ingress of moisture into the brickwork - and from there into any timber adjacent to it - it will be necessary to "seal" the brickwork and to "seal" the timber which you then place adjacent to it.

To do this, the brickwork must be as dry as possible. (A week of hot summer whether is a good idea!)

I recommend that you now search for marine grade "Epoxy Resin" (It is used for waterproofing/restoring wooden boats.)
This comes as a two part "mix" which can be applied, almost like water, to dry porous items and which will set within 24 hours into a hard impenetrable barrier to all moisture. Coat the dry bricks with this and allow to set.

Treat any residual "rot" in timbers which were cut with "wood hardener" made for this purpose. Replace the timbers which were removed due to rot, being sure to coat all of the edges with some fresh Epoxy Resin mix and allow to set. (As long as it is held in place while setting, the Epoxy Resin, when set, will form a "bond" and be much stronger than the timber.)

If, as is likely, there are gaps remaining in the old timber after this process, these gaps can be filled with waterproof epoxy resin/filler combinations, building fillers, car-body fillers etc. - prior to painting.
When you have done all this, you will have an epoxy coated and filled "block" which will resist water for several "lifetimes"!

 

[r0ckstarr]

Main reason it rotted was because they installed it in direct contact with the concrete so water wicks up wood.
What to fix this once and for all?
Replace the wood with PVC lumber, or replace the rotted wood and leave it about 1/4 up off the slab and have it wrapped with coil stock.
Even the coil stock needs to be just off the slab so it does not buckle as that apron moves up and down with the seasons.
No way would I use pressure treated, it would take months to dry out enough to coat.

I may have goofed my measurements on this one, but I am not afraid to take it down and redo it if necessary.

I took the old board down. The old one was too rotted to get an accurate measurement, so I measured from the top trim board down to the ground, subtracted around 1/4" and cut.

After cutting, I realized that the top board had sagged a slight bit when I removed the old board. I used another board to wedge up against the top trim board to put it back in place so that it was square again. When I put my new board up, my gap from the bottom is more like a half inch or slightly more.

Is this too much gap?