House Designs And Floor Plans

How to Build a Mother-in-Law Suite


Mother in-law suites are usually generated from three major types of remodeling, the basement remodel, the garage conversion and the suite addition. These are the most widely used plans. No matter which one of these projects you choose, you need to ask these question and follow the advice that I’m about to give you. The following paragraphs are  broad overviews. I will be expounding upon them in later articles.

1) Are There Any Covenants or Restriction to Keep You From Building a Mother-in-Law Suite?

Check with your subdivision, city and/or your county to see if they will allow two separate households to reside at the same address. You may be able to use same address “front, rear or side”. Even if you don’t need a permit to build your in-law suite always ask this question. Is there any public entity that may have judgment over your “zoning” privileges? Zoning can specifically define the use of your property.

2) Are Your Existing Utilities Sufficient For A Mother In Law Suite?

This could be a big one. Check the utilities of your existing home, to include the electrical service (power panel), the plumbing (both waste and water supply) and the heating/ cooling system to see if they are large enough to handle the new in-law suite. Use our “Concept Design Form” found at or website. Print it out and present it to a licensed mechanical, electrical, and plumbing contractor to evaluate the additional need that the remodeling project will demand. They will be able to give you a ballpark estimate on the cost according to your need. Caution, some of the MEP upgrades costs will be quite significant but they are necessary to a successful project that will add value to your home.

3) Hiring An Architect?

I suggest hiring a licensed architect. Here again, use our “Concept Design Form” listing the number of bedrooms, kitchen, bathrooms and other rooms you think are required to help an architect find the layout that will give you the best use of the square footage you have to work with. Remember that this space is for home care for a senior or other loved one. You’ve got one shot so get it right the first time. You may also need an architect’s seal on the drawing for the building permits. He will also make sure you meet compliance for emergency and secondary egress. As a Realtor I see clients shocked after spending hard earned money to remodel and find that without the correct window size or walk out, that it does not qualify for “living space”. That could mean a big fat zero gain when you list your home for sale.

4) Getting Estimates

The documents the architect produces gives you a devise to obtain complete estimates with fewer duplications and/or omissions. Getting three estimates is standard operating procedure. Give the contractor two weeks or fourteen working days for a bid dead line. Put in writing. Remember this is a buyers market. Be sure to have a schedule including a start date, a completion date and a payment schedule. Most contractors use the one-third system. Once again get it in writing, one-third on starting, one-third at the middle of the schedule, and one-third on completion. Get lien waivers from the general contractor as well as his sub-contractors and suppliers. Make sure the big ticket items are paid for, such as the ac-unit, copper wire and power panel box, bath tub with surround, roll-in shower, doors and windows, flooring, etc. Make their certificate of insurance for liability and worker comp part of the contract. One last thing you might want to get in writing is to make sure they supply a port-a-potty. This will help to keep your bathrooms clean during the construction.

5) Choosing The Right Contractor for Your Project

Pick a contractor that you feel at ease with. Check his references. Check all of them. How long has he/she been in business? Ask friends, neighbors and even your city about them. Use the Better Business Bureau. They may have a record of any complaints about them and how the complaints were handled. You must be sure that your contractor is trustworthy, responsible and prompt. This is a time of quick decision and close working space. I always feel as if I am at my clients beckon call. You never know when the electric will go off or the water doesn’t work. I’ve seen it all. The best-laid plans do go a stray. You probably have better odds at the casino than having a completed project end without some kind of hiccup. Building your mother-in-law suite can be a good experience. If you ask lots of question, do your homework, and choose wisely, you have a pretty good shot at enjoying the construction of your mother-in-law suite.


About the Author

Tom BillsTom Bills is the President of T. Bills Construction Co. since 1979 and is also the owner of In-LawSuite.com. Tom has completed many commercial, residential, and industrial projects with the highest standard of excellence, honesty, and integrity possible. Read more about Why Tom and his wife Barb started In-LawSuite here. Find him on Facebook and TwitterView all posts by Tom Bills →

  1. marilyn
    marilyn04-16-2011

    is a garage 26×30 gbig enough for a in law suite that includes washroom (shower) sink toilet and kitchen living room and bedroom

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