DIY Network

Digging In the Dirt: Best Type of Soil to Build On From "Blueprint for Home Building" episode DBHB-102

You've met the person who will be responsible for excavating your site and our host has discussed trees and vegetation and how saving them can lend aesthetic and practical advantages to your new home. Now it's time to find out what kind of soil is best to build on.

advertisement

	Figure A
	Figure B

How's My Soil?

Virgin ground is the best soil to build on, but many lots are composed of what's called "fill soil" (figure A). This is soil that has been altered or brought in from another location. Fill is brought in to build up a site or to replace bad soil. It's expansive or clay or something your engineer has decided. Most areas are all fill. You'll seldom find virgin ground unless you get way up into a rural area.

Note: Virgin soil is an area that has never been disturbed and has never had fill soil brought in. The only way you can find out where virgin ground exists is to go the city and have them research the area, and they can tell you if anything has ever been done in that area.

Even though it's best to have good virgin soil, but the fact of the matter is that you can achieve greater compaction (figure B) and greater soil values by bringing it in and then physically, from an engineering standpoint, compacting it on the site. You can achieve certain values that are even higher than what your natural soil would be.

Don't worry if your lot is composed of fill soil. With today's engineering technology, almost any site you choose should be able to have a home built on it. In fact, there is fill ground and engineered fill ground, and with the engineered fill ground you'll be told the compaction rate. A 100 percent compaction of fill ground is supposed to be as good as virgin ground, according to Greg Allen, a site supervisor for Hendolhurst Homes.

If your site is "not" on virgin soil and needs compaction, keep in mind that it will increase your budget. The average prices for compacting soil to create a "buildable" lot will run anywhere from $1,000 up to $5,000 or more, depending upon the size of the lot and how deep the excavation contractor will have to dig.

Note that it can be difficult to determine whether a site is composed of virgin ground, and if the city can't help, there's someone who can -- a Soil Engineer.
How Do I Find a Soil Engineer In My Area?

There are three ways to find a soil engineer in your area:

1. Get a referral from your architect. It's a good chance there's an engineer he or she can recommend and works with on a regular basis.

2. Contact the Associated Soil and Foundation Engineers Organization. They should have information on soil engineers in your area.

3. Ask your local building officials for a list of accredited soil engineers in your area.

Once your soil engineer gives you the okay to build on your chosen site, the excavation process can begin. There is, however, one special concern that rural homeowners may have to consider -- and that's how the soil on their lot will handle any waste or sewage concerns.

	Figure C
	Figure D

Does My Soil Need a Perc Test?

In order to find out whether you can even do a septic system on your typically rural lot, you need to have what's called a "perc test" (figure C) done on it. This test will find out how well the soil percolates and are things going to be able to be dissipated into the septic field the way they're engineered to be or are you going to have some problems.

Basically there are two ways to handle sewage transportation away from your home:

1. The first is to simply tie into pre-existing city sewage lines (figure D).

2. If you live "away" from populated areas, you may have to try a second option, which is to install a septic tank to contain your waste. A septic tank is a system buried underground that speeds up the decomposition process of waste. If you're building a home on a rural site that has no access to city sewer lines, have a soil engineer run a "perc" test on your soil. Once it's been determined that your soil has the necessary absorption qualities, your builder can then install the septic system to handle your home's waste.

Now that you know the type of soil you need to build and how it can affect your budget, in the next segment our host will tell you about another very important part of the excavation process -- surveying.

GUESTS :

Greg Allen
Site Supervisor
Hendolhurst Homes
955 Markman Park Rd.
Baden, PA 15005
Phone: 724-935-5658
Fax: 724-935-0884
E-mail: gcrbs@adelphia.net

Jim Sperdute
Surveyor / Project Manager
Sperdute Land Surveyors
108 Deer Lane
Harmony, PA 16037
Phone: 724-452-4362
Fax: 724-452-9357
E-mail: pasurvey@zbzoomnet

Craig Hill
President
Earth Systems Southwest
79811 Country Club Dr.
Indio, CA 92203
E-mail: chill@earthsys.com

Dave Watson
Architect
E-mail: architalk@att.net
Website: www.watsonarchitect.com