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Excavation

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  | Surveying and Layout | >>Excavation | Footings/Foundation  |  Foundation Options | Subrough Plumbing & HVAC | Dampproofing, Waterproofing and Window WellsWater and Sewer Laterals | Foundation Drain, Backfill and Rough Grade |
Basement Slab


Intro
Excavation is the process of removing earth in order to build a basement or foundation. Generally a backhoe, excavator or front loader is used to excavate for a basement. A front loader or bulldozer can be used to excavate for a stem wall (crawl space) or a slab on grade foundation. Besides digging a hole for the house, the excavator will backfill, install water and sewer laterals, rough grade, finish grade and provide gravel for flatwork. Before you excavate you will need to have the foundation lines and underground utility lines marked. The underground utilities such as gas, water and electricity must be marked by a utilities locating service. A utility locator service will mark the utilities with paint.

Marking Utilities
If you don't have the utilities marked you may be legally liable and/or fined if you hit an underground utility. Check your local laws before proceeding.
Remember that you will need 2'-4' over dig around the perimeter of the home. This gives you plenty of room to get the footings and foundation in.
Make a plan with the excavator to spread the dirt so that the concrete truck has access to pour the footing and foundation. If the concrete truck can't get close enough to the hole you will have to hire a concrete pump ($$$).

Foundation Depth
The depth of your foundation will be determined by several factors: the local frost line, required foundation above grade, level of the sewer line, garage access, and other possible factors.
Lift up the sewer cover and check the level of the street sewer line with a laser or transit level. Once you have that reading, check the level of your property. Your basement floor needs to be higher than the level of the sewer (for waste water to drain). Otherwise you'll need a sump pump to remove sewage from you house. Work with your excavator to make sure that the depth of the hole is correct.
Generally you'll need at least 1 foot of foundation above rough grade. For crawlspace foundations and slab on grade foundations the sewer is not a problem.

Contract
A contract would generally contain the following items:
• Price for excavation (usually charged by the soil conditions, and the square footage of the home, or size of the hole). However, some excavators charge by the hour only, because they aren't sure how much time certain hole will take due to varying soil conditions.

• Description of the work to be performed. Some excavators will offer a package deal for the complete excavation services, excavation, backfill, water and sewer lateral, Rough grade and finish grade.

• Cost for change orders

• Hourly rate for work not included in the contract.

Review
Double check excavation marks. Check that the setback from the property lines is correct. Check that the dimensions are correct, including the overdig. Make sure that the orientation of the house concurs with the plot plan.

Safety and Liability
• Safety is a major concern while digging a hole and after the hole is complete. Children are attracted to large piles of dirt and a large hole to play in. Make sure that you secure the site from unwanted traffic. Most states will make the property owner liable for injuries which occur on your property, unless precautions are taken to secure the site.

• Make sure that your footing and foundation sub is ready to begin immediately after the excavation.


Savings
• It costs extra to haul away fill. Try to minimize the amount of fill that is hauled away by spreading the fill out around the site. If you must haul fill off site, try and find someone who needs fill and is willing to pay for the hauling.

• Plan with the excavator to create a path or access to the footings and foundation so that he will make the hole easily accessible for the concrete truck, otherwise you may have to hire a pump truck for the footings and foundation.


Notes to the owner builder
Excavators price their work by project bid or by the Hour. Try and get a bid for the entire project which includes, excavation, backfill, installation of water and sewer laterals, rough grade, finish grade, and placement of gravel for concrete flatwork. This way you will know the exact amount for all the excavation.
If soil conditions are unknown, it is more likely that the excavator will want to work an hourly agreement. They reason that this is most fair to them and to the owner builder because without knowing soil conditions it is impossible to calculate a fair bid. If you make an hourly agreement keep good records of the work performed on site by each type of machine. Also get in writing the price per hour for each piece of equipment. Excavation equipment has built-in time meters making it is easy to track usage.