Siding Rotted Lower

[corbins]

Getting ready to paint our house. The lower part of our siding is rotting away where it touches the patio and landscaping. I think it is a poor design. How can I correct this? Cut away 6" on bottom and install HardiePlank or what would be the simplest fix that would work? See attached photo. Thank you.

 

[Chris]

There should have been an air gap at the bottom from the beginning. At least around me there always is to keep the water from sitting.

 

[Chris]

Do you know what is behind the siding at the bottom? Is there concrete for a stem wall or is it just a stud nailed to the foundation? If it has a proper stem wall you may be able to just cut the bottom inch or so away to make an air gap.

 

[WindowsonWashington]

+1

Needs to be cut back and should have a different trim detail and z-bar flashing.

 

[nealtw]

You won't know how bad it is until you cut it away, the landscaping and the concrete should not be right to the bottom of the siding, so expect some bad news.

 

[corbins]

I cut away a little and I feel foundation backing. Looks like it is some type of foam board on top of the foundation with some type of 4x8 sheets on top of foam board (not plywood). I guess I could drill a few holes to determine the top of the foundation. At that point, cut the rotted bottom away lower than the foundation. Do you agree and then what?

 

[Chris]

I wouldn't cut it too high but an inch or two should be enough as long as there is foundation behind it. A Z-bar won't hurt and will help seal things up but around here they are not used all that often.

 

[nealtw]

Is this the house or garage? Is this a slab house? Is there areas around the house where there is a different view of the bottom of the wall that might help explain what you have?

 

[corbins]

Its not a garage, its an add on to my house where you step down into that room. Here is a photo of the other side of that room. You can see there is foundation exposed. Thank you.

 

[nealtw]

Compare the hight of the siding from the two sides of the house to sio if you have siding below the level of concrete. Measure down from the soffet.

 

[mkklein68]

Pretty much all siding materials need to have a couple of inches gap between a horizontal surface the the siding. Even Hardie requires a 2 inch gap in its warranty coverage. The reason is that if the gap is too small, water can be sucked into it due to capillary action. Once in the gap, it can be absorbed into the material and cause rot or degradation several inches above the lower edge of the panel. Additionally, if you have problems with water overflowing gutters, water can splash onto the materials and possibly cause degradation.

This wall should have been constructed with a weather barrier (such as Tyvek) behind it. An even better construction would be one with a drainage plane between the exterior sheathing and the weather barrier. I am not sure about whether a flashing is needed without knowing more about the wall construction. Flashing is usually needed to direct water out of the wall assembly to the exterior. If the water cannot enter into the wall assembly, a flashing may not be needed.

That being said, I could not help but notice that a flashing was not installed between the exterior sheathing and the brick coping. Since one was not installed, you really need to make sure that the caulk between the brick and exterior sheathing is maintained.