The decision to add on a garage addition to a home is one of the best home improvement projects a homeowner can make. A garage addition provides great utility and can significantly increase the value of a home. Prior to actually breaking ground, however, a garage addition plan and garage addition costs estimates should be developed.

A garage addition plan starts with making initial sketches of the garage addition concept and evaluating how it will tie in with the existing home structure. Though most homeowners prefer a large garage, it is very important during this phase to consider proportions between the existing home and the new garage addition. To aesthetically look appealing from the road the garage addition length should not exceed two-thirds the length of the existing home. Otherwise the garage addition could overwhelm the existing home structure. The depth or width of the garage addition is less critical from an aesthetic standpoint, as it is usually less visible from the road.

Once the initial sketches have been completed, detailed garage addition building plans should be generated. Depending on the complexity of the garage addition either the homeowner or an architect can develop the actual garage addition building plans. In either case, the plans will need to include scaled drawings with dimensions, and cross-sectional construction views with constructional materials specified. The cross-sectional views should include from the concrete footings all the way to the peak of the roof. Each new transition from the footings up should be carefully drawn. Examples include: the footing/foundation transition, the foundation/sill plate transition, and the wall/roof rafter transition. The plans should also include a comprehensive bill of materials for the project. In addition, all property lines and appropriate setbacks should be clearly shown in the drawings.

Estimating the garage addition costs depends on who is building the addition. If the homeowner plans on acting as his or her own general contractor and performing some of the work (e.g. the framing) then costs will need to be calculated starting with the bill of materials generated during the planning phase. With a comprehensive bill of materials a homeowner can provide much of the list to any home improvement store where they can fill out the pricing information for the specific items for the project. For specialty items such as garage doors, garage door openers, and in some cases lighting and plumbing fixtures (if required for the garage addition) the homeowner may need to contact specialty stores for pricing. The subcontractors may also be able to provide some unit pricing (e.g. garage doors).

If the homeowner is acting as his or her own general contractor and will require subcontractors, then it is important that they identify early the subcontractors and review with them the plans and development schedule. Each subcontractor should provide a firm fixed estimate for the particular job based on the plans and bill of materials. In addition their bid should also include start/complete dates for the particular job.

With garage addition plans and costs estimates in place the homeowner can then proceed with pulling permits and developing a fairly accurate building schedule.

Once permits have been approved, construction of the garage addition can begin. It is important to note, however, that even with the best plans in place things happen and schedules slip. To mitigate schedule slips a homeowner acting as his or her own general contractor should factor in some buffer to the schedule and always be looking ahead several weeks during the entire project. They should regularly check with suppliers to ensure building material will arrive when required and should occasionally check with subcontractors to ensure that their schedules are still in line with your garage addition project.

With these simple planning, budgeting and scheduling issues addressed prior to the start of the project, building a garage addition can be a positive experience both pre and post construction phase.

For more information on building a garage addition see the Garage Addition Bid Sheet from HomeAdditionPlus.com. The Garage Addition Bid Sheet includes an extensive questionnaire (Request for Quote) that a homeowner can provide to prospective general contractors and subcontractors for bidding the garage addition. In addition, the Garage Addition Bid sheet also includes estimated costs and time intervals for constructing a garage addition as well as a list of key home material manufacturers. Finally, the Garage Addition Bid Sheet includes an extensive set of helpful tips and advice on making sure the garage addition is built properly and on time and budget.

Mark Donovan

Over the past 20+ years I have been involved with Building homes and additions to homes. I have completed many projects that have included: building a Vacation Home, Family Room Additions, and a Garage. I have also finished the upstairs on unfinished homes. My formal education and profession have been as an Electrical Engineer and Marketing Manager.