Question
Our condo complex is 30 years old, a fabulous Safdie design, the exterior is stucco built in Missouri on clay soil. As we begin to rework the landscape, I wonder what is the best approach (to prevent further wood rot and termites)to the area where the stucco meets the ground. Should the soil bank against the stucco to create a slope away from the home? I have no idea what treatment, if any, was applied to the stucco during construction.
Should we dig down to inspect and perhaps replace the waterproofing? There are places where raised beds are built next to the stucco. Good idea or bad?
I really appreciate your expertise with this!  

Answer
Your condominium sounds wonderful. I fully understand your concern about rot and termites in your present situation. And concerned, you should be. At construction, most building codes require that all wood exteriors and stucco be at least 6 inches above the grade of the land. This is for the protection of the exterior finish and walls of the structure.

It is possible that over the years the landscape maintenance company or grounds keeper has been adding mulch to the plant beds around your condo and as a result the elevation has encroached on the exterior siding. Wood and stucco should never come in contact with the soil, and preferably (as prescribed by building code, should be 6 inches above the ground and NOT have any organic mulches against it.

I would like to suggest to you that you re-grade your foundational plant beds so that you remove the catalyst for rot and termite damage. This may mean the removal/transplanting of some plants whose root systems have continually acclimated to the rising elevation as a result of the continuation of adding mulch to the existing beds. When completed, the grade should slope 3-4 degrees down away from the building structure. This method may seem time consuming, but it is the suggested renovation procedure for plant beds that encroach on foundations and entry ways where the accumulation of soil and mulches accumulate over time when plant beds are not maintained properly.

Another solution that may require less time is to install a moisture barrier that takes into account the present elevations. This is what we refer to as a quick fix for the symptoms, but it does not address the real problem of increasingly higher elevations of soil (plant beds) that are the cause of the rot and exposure to termites. To do this:

1) Dig down approximately 12 inches beyond the base of the stucco (approximate depth of foundation).

2) Once you have exposed the foundation and below elevation stucco and wood, thoroughly wash it with water using pressurized water so that the surfaces (foundation and stucco) are free of all soil.

3) Repair whatever stucco or wood that is rotten inspecting for termite damage as you do. I would suggest that while you have your foundation dug out that you call a termite company and have them treat your foundation as prescribed by them.

4) Once the surfaces are dried and repaired of any moisture or water damage, apply All Weather Roofing and Waterproofing Tar to the foundation and up 6 inches above the existing stucco that was originally below ground/mulch level being very careful to cover all surfaces approximately 1/4 inch thick.

5) Add one layer of 30# roofing tar paper so that it extends to the base of the foundation, pressing it firmly against the just added and still wet roofing tar. As you press it to the existing stucco, make sure that it follows the contour of the foundation and exterior siding closely so that no water pockets or air pockets occur.

6) Add another coat of All Weather Roofing and Waterproofing Tar to the first layer of tar paper and then add another layer of tar paper using the same technique as the first layer.

7) Once you have applied the 2nd layer of tar paper, you can backfill the soil immediately against the newly installed barrier. Use caution when back-filling so that you do not puncture or tear the barrier installed.

I would suggest that you contract with a termite/pest control company and get a termite bond for your building IF you feel that termites may be an ongoing problem in the future (especially if your structure is wood frame. Termites can eat an enormous amount of wood if given an open door to do so, and the result can be costly to a homeowner.

Please let me know if I can be of any further help or encouragement in solving your present issue. I remain,

Yours for a greener and more peaceful garden walk,

David Ward
[email protected]