Modular Home Construction
Modular Homes & Site Preparation and Foundations
Modular Home Site Preparation
- Modular Home Site Preparation - If your building lot is a jungle, you will need to clear the land of brush, trees and any other hinderances. The use of heavy equipment can save day and days of time. If you want to save money, this can be done by the home owner. You could add thousands of dollars to your building budget.
- Modular Home Location Survey - After the site is cleared, it is time to locate where on the your building lot you will be building your prefab home. Make sure to take into consideration all of the set backs listed on your building permit.
- Modular Home Module Access - At this time you will need to identify where you will be entering and leaving the property. Often you will need two accesses. One is temporary for the delivery and set of the modular home, and the other will be your future driveway.
Modular Home Foundation Installation
- Excavation for Modular Home Foundations - Having marked out the location of your home with batter boards, the excavator will arrive and dig your foundation. If some of the fill needs to be removed from the site to make the site accomodate the home, the excavator will haul away excess fill.
- Basement Utility Layout - If there are going to be any utility service entries, this is the time lay them out so foundation walls do not need to be drilled through. Preparing your prefab homes foundation space will be discussed with your builder.
- Modular Home Foundation Footings - The mason will arrive and construct the prefab home foundation footings for the foundation. After the footing are installed, most state and local code requires a foundation footing inspection by a building inspector. The footings and foundation are key to the set set of a modular home. The foundation needs to be square, plumb and installed to the correct dimensions. The squareness of a system built home such as panelized, SIPs or prefab is very important. Site built homes can compensate better but a crappy foundation is a crappy foundation.
- Modular Home Foundation Wall Installation - Your foundation wall will be installed on your footings. This wall could be concrete block, a system built foundation, insulated concrete forms (ICFs) or a poured wall. Often people choose prefab foundation wall systems for their prefab home.
- Anchor Bolts and Sill Plates - The modular home foundation will need to have a sill plate installed so the band joist do not sit on concrete. The sill plate should have seal installed between the foundation and the sill plate to stop moisture from wicking into band joists and to stop air from entering your foundation. The sill plate will be attached to the foundation with bolts or tie down straps.
- Foundation Drainage - Keeping your prefab homes foundation dry is imperative to an energy efficient, durable and healthy modular home. The foundation drain consist crushed stone and perforated pipe that drains ground water away from the prefab home foundation.
- Sump Pump - Before pouring the floor it is wise to install a sump pit so that if in the future you need to drain your basement, your home will be ready with a sump pit.
- Insulation and Vapor Barriers - Prior to pouring the modular home foundation floor, a vapor barrier and insulation should be installed. The vapor barrier will minimize ground moisture from entering the prefab home foundation space and the insulation will minimize heat loss. The insulation will keep your floors warmer in the winter. If you have a walk out basement, it is imperative to install insulation at the exposed edges of the foundation.
- Pour Basement Floor - Your modular home foundation is now ready to have the concrete poured. It is wise to pour foundation floor two or more weeks before the modular home is deliver to the site. When concrete cures tons of moisture will evaporate into the foundation space causing problems. It is wise to run exhaust ventilation from a new foundation for a month after the modular home has been set on the foundation.
Additional Site Work for Modular Homes Site
- Backfill and Rough Grade - It is wise to back fill the modular home foundation prior to the home being set on the foundation. A prefab home with a backfilled foundation will be easier for the set crew to install the house and minimize crane. In addition is easier and safer for set crews to position the modules on the foundation when the foundation has been backfilled.
- Crane Base - Before the crane arrives on the site to set the modules on the foundation, a crane base will need to be available next to the modular home's foundation. Crane bases should measure thirty feet by thirty feet for the crane and the crane's outriggers. Often two B stone will used for the crane base.
- Sill Plates - Sill plates need to be installed on the foundation. The sill plate is usually a 2x6 pressure treated lumber for the home to be placed on. Sill plates are necessary to protect the modular home from foundation moisture.