5 Tips for Planning Your Roof Addition

plan your roof addition properly

Designing a roof addition for your home doesn’t have to be complicated. Ideally, the completed addition will blend seamlessly into the original part of the house. Follow these steps to ensure the process goes as seamlessly as possible.

1. Gather legal documents.

Serious home renovations and add-ons require a fair amount of planning.

Before anything else, you'll want to track down and organize a few legal documents.

Determine the plot plan and property lines of your space and how close the new addition comes to existing neighborly buildings. This is crucial, as you want to ensure the new addition does not fall outside proper zoning laws.

Carefully examine plot plans and surveys, do your research, and ask your local zoning experts about laws and regulations.

Do not skip this step. Stepping outside of jurisdictional red tape could mean your new addition will need to be torn down. Gathering the necessary information and following your area's local guidelines will ensure your roof addition is legitimate.

Find a qualified roofing contractor

2. Plan out a realistic budget.

man planning out budget

Homeowners can have wild expectations of an amazing addition being built quickly and with little disruptions to their original plan. This is rarely the case, and it’s best to realize that even small projects can change and cause hiccups.

Create a realistic plan by budgeting for the remodel accordingly. Develop a budget that includes:

  • estimate of project cost
  • potential increases in property taxes
  • cost of larger utilities
  • contingency for unexpected changes (we recommend 20%)

Be disciplined and stick to your budget. Homeowners can get carried away with additions and end up footing a much larger bill than anticipated.

Create an outline, calculate costs, and you’ll enjoy your new space without worrying about the high economic impact.

Phase of Addition Cost 
Framing $6 - $8 per square foot
Vinyl Siding $7 per square foot
Electric Wiring $50 - $100 per hour
Foundation $75 per cubic yard
Asphalt Shingles  $80 - $100 per square foot
Plumbing $250 - $300

KEEP READING: 5 Tips to Keep Your Roof Replacement Within Budget

3. Choose a roof style.

As a general rule of thumb for all roof additions, follow the existing roofline and pitches.

The new addition should match or at least mimic the same lines of the home roof. For added balance and symmetry, install matching roofing materials, windows, and siding.

Roof Extension

Adding an extension is a simple, relatively low-cost solution that blends in naturally with the main house. This is easily accomplished when adding on to the gable side of a house (the exterior wall on the side of a home that goes all the way up to the roof’s peak).

However, because gable ends are typically on the side of the house, this isn’t always suitable for roof additions. Typically, additions are installed in the front or back of the house to better enjoy yard space.

Shed Roof

A shed roof is the simplest solution to adding a roof extension.

It’s designed as a single slope that is attached to the original house at a high location and slants downward to the outer wall of the addition. It’s an easy design, uncomplicated to build, and budget-friendly.

However, it’s easily noticeable as an addition. If not done properly or installed by a contractor who doesn’t care about aesthetics, it can appear sloppy and diminish the home’s value.

Gable Roof

A gable roof consists of two slopes. Rather than a single slope, like a shed roof, two slopes meet at a peak running down the middle of the roof.

When designed to match the angle and proportions of the other rooflines on the house, an addition designed in this fashion adds visual interest and character.


Dormers, while similar to a small gable roof, are a bit more complicated and pricey. Dormers extend out from the main room at a 90-degree angle and typically incorporate windows.

They’re useful if you’re planning a large addition, like expanding the top floor of your home, as dormers effectively raise the ceiling. Dormers are also a great way to tie together the roof of your home and the roof of your new addition.


4. Hire a reputable contractor.

While there are some hardcore DIY-ers capable of building a seamless home addition, the majority of homeowners should hire a professional contractor to complete the project.

The reality is: Home additions are expensive and often require financing from a banking institution. If you’re borrowing money from a bank, they will likely require that you hire a licensed professional for the job.

Hometown Roofing Contractors makes it easy to find the right local roofing contractor for your addition project. You can view multiple company profiles, see how other customers rate their services, and request quotes from as many roofers as you'd like.

House additions are complicated projects and require more than just a roofing contractor. A respected roofer will often have relationships with other trusted general contractors to help complete the addition in a timely manner. 


5. Determine price and payment schedules.

couple speaking with contractor

Once you’ve found a suitable contractor for the job, agree to a total cost of the addition before moving forward.

After settling on a sum, get it in writing, preferably in a legally binding document. Determine the schedule of the project and when you can expect certain critical phases to be completed.

This will help you in negotiating how much money to pay up front and how much to hold off on until the addition is done.

It’s reasonable for contractors to expect some money in advance and after milestones during the course of construction. Be aware of contractors asking for a large sum before starting any work.

It may be a tough conversation to have, but you should know exactly what to pay and when prior to any ground being broken.

Keep in mind that even the best-planned projects run into problems. This is why having a contingency allotment in your budget is a great idea. You may change your mind about styling options, fixtures, or square footage; or the contractor may need more supplies than originally anticipated. All of these factors can greatly increase the cost of the addition and cause tension between you and the contractor.

Minimize potential conflicts by clearly laying out plans, a payment schedule, and other contingencies at the start of the project. 

Find a qualified roofing contractor