Builder's Guide to Room Additions
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Introduction | Table of Contents

Chapter One
Starting Out

Construction of room additions and conversions is a $150-billion-plus per year business in this country. If you're already in the home-building business, you have the background and skill needed to succeed in this type of business.

This book will show you how to get jobs, plan the work, and then complete the project so you make a decent profit. We'll cover the problems you're likely to run into when converting basements, attics and garages or adding rooms to existing houses.

Both room conversions and room additions add living space. In that way they're both similar. But there is one major advantage to doing room conversions - you can work on conversions without worry about delays due to bad weather. That's the advantage. The disadvantage to conversions is that you have to work with the homeowner's family close at hand (and maybe even "helping" in the project).

Selling to and Satisfying the Homeowner

Homeowners add space and convert rooms because they need more living space. Additions and conversions solve an immediate problem. And they also provide a long-term advantage: better resale value. Make value enhancement a selling point when bidding any room addition or conversion job. Reroofing with asphalt shingles doesn't do much to enhance the value of a home. Everyone expects a house to have some suitable roof cover. But adding a porch, a bathroom, or a bedroom will increase the value of nearly any home. A wise owner understands that adding or converting space increases resale value.

I've found that homeowners who are adding a room or converting an attic or basement are good prospects for other work. Many will want the rest of their house brought up to the same standard as the new or newly-converted space. Be prepared to take on these profitable jobs. The extras can mean the difference between a decent profit and a bonus profit.

But here's a tip that can prevent disappointments. No matter how well you know your business, let the homeowner call the shots. Supply what the homeowner wants, not what you feel the home needs. Any design that doesn't take into consideration the desires of the homeowner isn't a good design, no matter what you think about it. A builder who has his own ideas about fixture colors, or floor and wall tile, is well-advised to keep those opinions confidential unless the homeowner asks for advice.

Of course, you have to point out things that can't work. For example, building codes and structural requirements limit what any builder can do economically. Of course, anything is possible on an unlimited budget. But you won't have many clients like that. If what the owner wants can't be done on a reasonable budget, be ready to explain that. The homeowner expects you to point out flaws in ideas he or she throws your way. After all, you're the professional.

Each job you take will have its challenges. And the greater the challenge, the better your chance for profit. The trick is to identify problems and solve them before they dissolve your profit and erode your reputation.

Labor is a budget-buster on most jobs. Here's a rule of thumb to follow when estimating labor costs: Assume that it will take twice as long to do most remodeling tasks as it does to do the same work in new construction. The manhour charts in this book are based on remodeling work and should improve the accuracy of your manhour estimates.

Designing an Addition

Before beginning serious design work, always find out what the code requires. For example, codes and zoning ordinances govern setbacks from property lines and streets. Most codes won't let you extend the front of a dwelling any nearer to the street. On narrow sites, the only direction you can expand may be to the rear. Be sure you know what the restrictions are. If you build an addition where an addition isn't allowed, don't expect to get paid for it.

When designing a room addition, approach the project about the same way you would if you were planning to build a house. But keep in mind that you're faced with limited options. Your choices of design, placement, materials, and access will be restricted. The design of any addition or conversion should blend into the design of the original home. Don't let your addition look like an afterthought. You're weaving a blanket, not making a patchwork quilt.

Still, there's plenty of room for innovation and creativity, as you'll see in later chapters. Common sense and a good eye for exterior appearance are your best guides. If you don't have the latter, use the former, and consult an architect.

Before the planning goes too far, think about conflicts and restrictions. For example, if there's a septic tank in the yard, mark the exact location before design goes too far. If the add-on will be on a concrete slab, think about drainage. Don't assume anything about the existing site. Do some investigation. For example, consider removal and replacement of topsoil. And what about power lines? I know of one builder who didn't give enough thought to an overhead power line. As it turned out, the power lines had the right to be right where they were. His wall framing had no rights at all. He had to remove the framing and relocate the addition elsewhere, at his expense.

As I said, your selection of materials and design options is almost unlimited. But I recommend against being a pioneer. You're working for homeowners who have their own tastes and prejudices. Your objective is to develop designs that are both acceptable to the owner and a good value. And no one solution fits all. Tailor your recommendations to the site, the owner and the best combination of skills and materials available. For example, a log house might be a good choice for a wooded hillside cabin. But I wouldn't recommend it for downtown Dallas.

Sizing an Addition

Avoid making a major addition to a small home in a neighborhood of small homes. For example, don't recommend investing $150,000 in a major addition to a home in a neighborhood of homes selling for $150,000. Nothing you can do will make one home on a street worth twice as much as any other home on the same street. That would be foolish. Instead, recommend adding a fourth bedroom and a third bathroom in a neighborhood of mostly four-bedroom, three-bath homes. That's always money well invested, especially if property values are increasing.

Consider carefully what's best for your client. Don't recommend a 10 x 12 addition if there's space for a 12 x 14 or larger room. How much more would it cost to go for the larger size? Suppose you can build the 10 x 12 addition for $50 a square foot. For an additional $2,400, you can build the larger room. You owe it to your client to discuss the option of going for the additional space. If your client is thinking about a 12 x 14 bedroom addition, explain the advantages of a 12 x 16 addition that includes an additional bathroom. Most homeowners understand that a 12 x 14 room doesn't cost much more than a 10 x 12 room. They'll also appreciate the closet space you can build into that extra 48 square feet of floor area.

When a homeowner is thinking about adding space, particularly a bedroom, suggest adding a bathroom as part of the project. That's nearly always a good choice if space is available on the lot. An extra bathroom increases resale value and costs much less when added during other construction.

A bathroom may, of course, be the purpose of an addition. Suppose you're adding a bathroom to a master bedroom that's 12 x 12 (hardly a size that can be robbed of space for a bathroom). The adjoining rooms can't be spared for conversion to a bath. The owner doesn't want to close off any of the existing windows. The only solution may be to expand outward. Build a bathroom adjoining the master bedroom. Figure 1-1 shows an example.

Where feasible, put the bathroom where there are existing water and drain lines. That saves money, of course. But the cost of running those lines a few feet farther isn't very much.

And always try to keep room additions modular. Modular construction reduces wasted materials and cuts installation time. Check out the ideas in Chapter 8 before you finalize any design.

Adding to an Existing Structure

Every room addition requires joining two parts -- the existing with the new. The completed structure should leave no obvious sign of the distinct parts. I'm sure you've seen add-ons that looked as if two different buildings were hauled in and shoved together. Blend your add-ons into the existing structure by using similar finish materials. Occasionally you may want the room interior to have a different look than the rest of the house. But the exterior finish should always match the existing building.

It's nearly impossible to match brick or stucco exteriors. The color and style of brick, block or stucco was probably discontinued years ago. Even if the same materials are still made, the existing finish has probably faded as it aged. The best you can do is get the closest match possible and then paint the entire house. That's not going to be a popular suggestion with most homeowners.

Older homes usually have molding and trim styles that are no longer made. You'll have a hard time finding a mill to duplicate fancy trim such as spindles and scroll work. You might have to compromise on trim that's similar but doesn't match exactly. Another solution is to look for an older home in a neglected neighborhood. Find a home with trim of the style you need. Then try to negotiate with the owner - if the trim is salvageable.

Neighborhoods where preservationists are repairing and restoring old homes usually have a source for the trim you need. One good supplier of old-style trim is Vintage Wood Works, Highway 34 South, Box R, Quinlan, TX 75474. Phone 903-356-2158.

Matching old asphalt shingles is seldom worth the trouble. You'll probably want to replace the entire roof cover if the addition requires extending the roof line. Otherwise, your project will have that add-on look no matter what you do.

The ridge and slope of a roof, the roof's eaves and rake, the wall's plane and comers form the lines of a house. Each of these is part of the building line. Adding on at a building line is called line or plane joining. That's what was done in Figure 1-2.

At first glance, plane joining seems to be the best way to blend a new addition into an existing house. But it isn't. Any time you join at a building line, the joint will be obvious. The addition is going to look like an add-on. Matching exterior finish materials is nearly impossible if the joint is at a building line.

Any flaw at the building line will emphasize the joint between the two parts of the home. Say the roof ridge isn't level, the roof surface is wavy, or the wall is tilted. Any of these will work against you, making anything you do look bad.

Don't try to join one smooth surface to another smooth surface. Go for a break or offset. Step the roof line up or down where the addition intersects the roof line. Offset the foundation forward or back. Figure 1-3 shows several ways to make a break for a room addition.

A wall break can also smooth the transition between different exterior materials, such as where brick or stone joins wood siding. A home looks much better from the curb when you create a real break at the point of intersection.

Measuring Major Components

Avoid surprises when you build an addition. Be sure you know all the key measurements of the existing house. Establish finish floor lines, ceiling heights, rafter height, placement of doors and windows. Record all the measurements that might affect the room addition.

Figure 1-4 shows how to measure the key dimensions. Note that the roof overhang at the eaves is one of those key points. The overhang on the addition and the existing home should be the same.

From experience, I've learned it's best to find the finish floor height at several points. One of these points should be at the wall opening to the room addition. If the floor isn't level at this point, you'll have to adjust the floor height in the addition accordingly. It's no use creating a dead level floor in the addition if the floor in the adjoining room isn't exactly level. The owner will think you're the one who made the mistake. If you know that the existing floor isn't level, make adjustments so the two floor levels match.

Demolition

Demolition is a major part of most room addition jobs. You'll have at least some removal work on almost every room addition or conversion job. Unfortunately demolition is probably the hardest part of most jobs to estimate. Until you open up that wall or break out that foundation, it's hard to know what you'll find. But don't give up. Demolition estimates don't have to be pure guesswork. There's a lot you can do to anticipate costs. For example, you should be able to forecast problems of limited access on nearly every job:

• How close are the adjoining properties and buildings?
• How much space is there to handle and load debris?
• Will you have to work from a narrow or almost nonexistent yard?
• Is there enough space to back a truck in to catch the shingles as you remove them?

Answer these questions before beginning your demolition estimate.

How do you estimate the manhours required to remove a door or a partition wall? And if it's a load-bearing wall you're removing, don't forget to include the labor and materials required for temporary bracing. Good judgment and cost records from previous jobs will always be your best guide. Information in construction cost reference guides may help. (Several estimating books are described at the back of this book.)

Here's a rule of thumb to use if you don't trust your judgment, have no cost records and don't believe in published estimating data. Simply figure demolition manhours will be the same as installation manhours. For example, assume it takes about 1.5 manhours to lay a square (100 square feet) of three-tab square butt shingles on a roof. If you have no better numbers, assume the same amount of time (1.5 manhours) to remove a square of asphalt shingles. In most cases, this estimate will be generous - you'll need a little less time than estimated. But it's wise to be at least a little conservative when estimating any demolition. If you find something like lead paint or asbestos shingles, you'll need it.

Conserving Used Materials

During your negotiations with the homeowner, you may be asked to salvage and reuse existing materials whenever possible. For example, I've had owners ask me to reuse the sheathing and rafters I'm demolishing. I recommend avoiding salvage of framing. It takes too long, adding more to your labor cost than the price of new sheathing and rafters. That cuts into your profit. Instead, quote the job using all new materials. That ensures a professional job - and a profit. If the owner insists on salvage of materials, fine! Set them aside and let the owner deal with the problem. Don't try to install them yourself.

A word of caution on demolition. Sweep up all the nails and staples you take out during demolition work. Loose nails and staples are a safety hazard. Too often I've had employees, owners or children hurt by nails or staples removed during demolition. Leave the job site broom-clean at the end of each day to reduce the chance of injury to the homeowner and neighborhood kids. I try to keep nails and staples in my apron as I take materials apart. Provide a covered tin or box where nails and staples can be collected until they're ready for the trash bin. The homeowner will appreciate your thoughtfulness and your professionalism.

The Importance of Paperwork

I know home improvement contractors who work on a handshake without the benefit of written specifications or contract. I don't recommend doing business that way - even though I've been guilty of the practice more than once. When you've built a reputation in the community, clients tend to trust your word and honor your invoices. Just listen to what's needed, do the work, and present your bill. I've done work that way for repeat customers and have had very few problems - yet!

No matter how flattering it is to be trusted to work on a handshake, I recommend drawing up a "little memorandum of our agreement." It's not that you don't trust the homeowner. It's just that verbal communication is no more permanent than human memory and is always subject to interpretation. The homeowner knew exactly what he wanted and explained it to you precisely. And you listened carefully and knew exactly what he meant. It's just that he left out one little part. But that's OK because you already had that in mind (or at least thought you did). So you never found out that he didn't know that you didn't know what he knew.

Great !

That's your loss if you didn't put it in writing. My advice: Put it on paper. A written agreement protects both you and your client. It helps avoid disappointments that could become a major loss. The process of putting a verbal agreement down on paper will usually expose most potential misunderstandings. I think of it as cheap insurance.

The Contract

Figure 1-5 is a sample proposal and contract form you might want to use. This form includes the notice required by federal law that describes the customer's right to cancel. Figure 1-6 is the customer's cancellation notice.

Figure 1- 7 is a job specifications form. It becomes part of the contract. This is where you specify the work to be done and materials to be installed.

Here are two contract drafting tips that could save you many times the cost of this book in the next year alone.

Tip One: The most important part of any contract is where you list what's excluded. Most construction disputes begin with the owner saying, "Hey! I thought you were going to include. . ." Don't leave room for that argument. Right under where you list what's included, list what's not included.

For example, if you're reroofmg a home and only shingles are included in your bid, consider writing the following words into the agreement:

No flashing, sheathing, decking, masonry patching or replacing of rafters or vents is included in this proposal.

That should avoid most misunderstandings. It also puts the owner on notice that additional work may be needed, depending on what you discover when work begins. Of course, you're happy to bid on this extra work. But it will be at extra charge. Nothing but shingles is included in the contract.

Tip Two: Describe in the contract the materials you'll install, not the job you'll do. For example, if you're reroofing a home, the contract might say:

Furnish and install 1,600 square feet of three-tab, 240-pound, Class 3 composition shingles.

The worst thing you could say in the contract is "Reroof the home at 321 Main Street." What does that include? Who knows? Probably lots of flashing, sheathing, decking, masonry patching, rafters and vents.

I hope you get the point. You're a construction contractor, not an insurance company. If you discover that the deck is rotten, flashing has turned to dust and the sheathing won't even hold its own weight, that's not your loss. You're bidding the shingles. Everything else is extra.

The Plans

Your plans for an addition should be so clear and specific that anyone with construction experience could build what's required. Whether the plans are a roll with dozens of sheets prepared by an architect or a single sheet of 8-1/2 x 11 paper, the measurements have to be clear.

Detailed plans will show a foundation plan, a basement plan if there's a basement, and front, rear and side elevations. A more complex job will include section and detail drawings.

A foundation plan shows the length and width of a structure, as well as its shape. It includes information on materials used for footings, pillars and foundation walls. An 8-inch-thick concrete footing 18 inches wide may be expressed as 8/18. A standard 8 x 8 x 16-inch concrete block foundation may be written as 8 x 8 x 16 CB. Figure 1-8 shows a foundation plan that's typical for a room addition.

A floor plan shows the work as it would be seen from directly above. The floor plan will show the location and size of wall openings, the door swing (right or left hand opening), room sizes, and wall thicknesses. It can also show the placement of light fixtures, wall switches and receptacles, and joist size and spacing. Figure 1-9 shows a floor plan for an addition. The front and side elevations of the addition could also be drawn as shown in Figure1-10.

Elevation views show vertical dimensions. The dotted lines show what is below ground level. Exterior finishing materials and roof shingles may also be included on an elevation view.

Section and detail drawings are close-up views. They should eliminate any question about the critical sawing, fitting, and construction procedures. Figure 1-11 shows typical section and detail drawings. The main wall section shows a cross-section of the wall from footing to ridge.

Here’s how I interpret the construction details in Figure 1-11:

There’s a 2 x 10 header joist, a 2 x 10 floor joist, and cut-in blocks between the floor joists. Ceiling joists are 2 x 8s spaced 16 inches on center. They rest on the top plate and have 2 x 8 cut-ins. The rafters rest on a continuous 2 x 6 plate on top of the ceiling joists. In most plans, the rafters are sawed to fit directly on top of the top plate. This plan allows for a horizontal soffit and a 2'6" overhang at the eaves. The rafter cut is 14'4-9/16". The roof pitch is 5/12. The distance from the bottom of the ceiling joist to the top of the ridge is 6'61/2”. Studs are placed 16 inches on center. The studs rest on a 2 x 4 sole plate and have a double 2 x 4 top plate. The top of the window is 6'9" above the finish floor. It shows the type of header that's commonly used for window and door openings in load-bearing walls. The basement ceiling height is 7'1-5/8". The main floor ceiling height is 8'1".

The window panel drawing shows construction details for the panels under the front windows. The 2 x 10 sill is a joist header.

Figure 1-12 shows the type of detail drawing that's usually provided with stock house plans offered by a plan company. This sheet shows a series of detail drawings that could be used on many houses. Your local code may prohibit some of the details shown on stock house plans. Get the counsel of your building department on what the local code requires.

Figure 1-13 is a material description form. I use a form like this to list information about the quality, size, type, style, and manufacturer of materials I plan to install. There isn't enough room on floor plans and elevations to describe everything you want to say about the materials you expect to install. Use this form to list all of that important information so you have an accurate, detailed, permanent record. Make it a part of the construction contract by referring to it in the contract. There's less room for controversy if a form like this is made part of the contract.

Use these or similar forms on each job and you'll eliminate most conflicts and misunderstandings. If you can't find a vendor who sells construction contract forms, copy the forms in this book and use them.

Who Pays for the Plans?

Floor plans are usually done at the expense of the owner. If you draw up the plans, be sure it's understood that you'll be paid for them. Include your fee in the bid. Don't hand over any plans until the contract is signed. Otherwise, the owner can shop around for a cheaper builder, using your plans.

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