The average cost for a room addition in the U.S. runs between $50,000 and $65,000. You may want to save that outlay by undertaking the effort yourself. But, be prepared.
Most room additions should be carried out with the help of professionals. But if you’re good with tools and have the time and patience, there are projects that can be completed with minimal help.
If you’re adding onto an existing home, some parts will definitely require the services of a professional. Amateur builders are simply not equipped to lay foundations, deal with complex zoning or permit issues, and the like.
But, if your project is simpler you may be able to carry it out yourself. Converting an attic to an additional bedroom is within the ability of most who have some experience with home projects. Converting a closet is usually even simpler. Dividing an existing room into two can sometimes be carried out in a few weekends.
First, look online for one of the many ‘plans’ sites. Room plans are often available for anywhere from $10-$100, often toward the lower end of that estimate. Shop around and ask for samples, since some are as simple as a few sketches containing ideas, while others have complete blueprints and plans.
Measure the space and decide whether you will be adding walls – such as a divider for an existing room – or tearing some down. Get estimates for 2 x 4’s, panels, moulding, screws and nails, etc and form a budget.
One plan for dividing an existing room, for example, is simplicity itself. It uses a homosote panel – a kind of pressboard in service for over 100 years – held between strips of moulding. The panel is placed along a line to divide the room and held in place at the top with double-sided tape or L-braces screwed into studs. Some materials provide soundproofing as effective as ordinary plaster drywall.
Next up in the level of difficulty is the classic skeleton of 2 x 4’s. With an assistant to hold ends, tools, etc this can be erected in a few weekends. Be sure to take the time and care to make cuts at right angles and fit pieces together precisely.
Some are simply nailed together, but L-braces will provide for better structural integrity. Sections, and sometimes the entire wall, can be constructed on a cleared floor and hauled up into place.
Be sure to develop plans for any needed wiring or computer cabling before you get out the hammer and nails. Unless you have extensive experience, electrical work is almost always better carried out by a professional. Non-professional wiring work can violate home insurance policy rules, so read the fine print and consult your insurer.
Be sure to research any permit, environmental, safety codes or other legal issues before getting started. The room addition inspection and permitting process usually has different components. Basic foundation and carpentry aspects are covered. But, depending on the kind of construction, plumbing and electrical permits may be required. You don’t want city, county, or state inspectors requiring you to make expensive adjustments after you’re done.