Although it is more convenient for a contractor to build on a site without obstacles such as trees, native vegetation, and boulders, some but not all contractors will go to great lengths to preserve as much natural vegetation and as many other landscape features as possible. Do not assume that the preservation of your site will be a priority of the same magnitude for a contractor as it will be for you. To clarify your desires and the contractual obligations of the contractor in this regard, you can formalize site preservation intentions by stating them as part of your contract.
Here is an example of site specifications created for the purpose of preserving the natural features of the site and preventing pest infestations as a result of the clearing process.
It is the owner s intention to preserve the natural vegetation and land features of the site to the greatest extent possible.
• The owner and architect shall approve the site layout prior to the digging of the footings.
• Topsoil and large boulders shall be stockpiled for future use.
• All trees designated for removal from the building site are to be marked for review by the owner or architect.
• All tree stumps and dead foliage shall be fully removed from around and under the
building site and disposed of offsite so they do not attract termites and other pests.
• The owner and architect shall determine which trees are to be transplanted or maintained during construction.
• The construction area and access to it shall be as small as is reasonable to facilitate construction of the home. This area is to be clearly demarcated and roped off to prevent any destruction of natural terrain outside the area by construction vehicles.
Many mold problems originate with poor drainage around the building perimeter, which can cause water to puddle against the building and sometimes to seep inside. Although less prevalent in dry climates, mold is still a serious health threat, especially in flat — roof construction where canales or scuppers are used for roof drainage and erosion around the discharge is common. An adequate roof overhang will be the first line of defense in keeping water away from the building envelope. Good site grading will be the second line of defense and a perimeter drainage system in combination with stem wall dampproofing as described in Division 7 will constitute the third component of a comprehensive rainwater management plan. The following specification for surface water runoff management is recommended: [4]
• All canales, scuppers, and downspouts shall have splash blocks and an adequate drainage path away from the building.
Sometimes the soils under brick walkways, under interior brick pavers, surrounding the structure, or under the structure itself are treated with insecticides or herbicides. This practice should be avoided. Many people have become sensitive to very low levels of pesticide exposure. Children are especially vulnerable. Some harmful agents will remain potent long after the building is gone. Where soil treatment is mandated or otherwise unavoidable, we recommend the use of boric acid, dia — tomaceous soil, or other least toxic measures. (Refer to the section on integrated pest management in Division 10.) You may wish to specify the following:
* Do not treat soil with manufactured chemical treatments.
* Treat sand surfaces under floors and brick or stone walkways with diatomaceous soil. Inhaling dust from diatomaceous soil is hazardous and proper precaution should be used during application.
* Use barrier cloth under exterior walkways to prevent weed overgrowth.
Petroleum tar, which is the main component of asphalt or “blacktop’ paving, is carcinogenic and should be avoided. Not only does it emit harmful vapors during installation but it also will volatilize when heated by the sun. More healthful options include concrete slab, concrete or brick pavers, and paving stone or gravel over a well-drained and compacted base.
The following products are innovative ways to stabilize a road base without the use of asphalt or concrete paving:
• NaturalPAVE XL Resin Pavement: A combination of nontoxic, environmentally friendly organic and inorganic resin materials that creates a high — strength pavement.
• Perma-Zyme: A biodegradable and environmentally safe road stabilization enzyme product that works by lowering the surface tension of water, promoting penetration and dispersal of moisture. This causes hydrated clay particles to fill voids in soil so that it forms a tight, dense, and permanent stratum.
• Stabilizer: A colorless, odorless psyllium — based concentrated powdered soil additive for dirt or crushed stone surfaces. Stabilizer binds and flocks aggregate screenings to provide a firm natural surface for pathways, trails, and driveways.
Where asphalt paving already exists or is the only paving option available AFM DynoSeal Driveway/Asphalt Sealer may be used. It is a low-odor elastomeric sealer and top coating for asphalt surfaces that helps to reduce the outgassing and odors generated by new asphalt.
International Institute for Bau-Biologie & Ecology. Home study courses, online study, and seminars. PO Box 387, Clearwater, FL 33757,727-461-4371, buildingbiology. net.
