Expert: Ted Barnhill (Principal, Design45 LLC) - 6/7/2008

Question
Hi Ted,

Our family lives in a 2 story house with finished basement near Calgary, Alberta in Canada. The main level is 30 ft in length and 28 ft in width. Our Kitchen opens up at the back of our house into a sloping backyard. We are thinking of extending the entire house at the back (on all three levels) by another 14 feets. We have taken a quote from a local builder and are now looking for a suitable architect. My question to you is this 1) Will this kind of renovation create long term structural issues and reduce lifespan of the house. 2) How will the builder take out the load bearing wall at the back of our house and still support the house.  3) Will this project require us to move out while repairs are in place. 4) How easy it is to cut thru the existing foundation to open up existing house to the new addition. 5) Is this kind of Addition advisable?

Please advice

Regards

Answer
Shailesh,

Your proposed project is significant - it does have the potential to dramatically affect your home, and you are right to be asking these questions.  However, if you consult with competent professionals with current knowledge of construction techniques, and follow their best suggestions, you should feel comfortable that your home will be improved, and not compromised.

To specifically address your points:

1. In our remodel/addition work, we and our consulting engineers routinely discover undersized structural elements, and remedy these existing problems.  Oftentimes homes were built using old rules of thumb, and never properly engineered.  I expect your home will only be made stronger if you consult with an architect, engineer, and/or specialized residential designer.  You will want to be sure that your designer can properly detail the construction to prevent moisture/mold problems within walls, and that your contractor has a proven record of conscientious construction.  Today's homes are built very tight, and any moisture that gets into a wall and isn't provided a way to dry out will cause mold and possible rot.

2. New structural headers will be required to pick up existing and new loads.  These will rest on columns that transfer the load to footings - either existing or new depending on the amount of load.  Your architect or engineer will handle this.

3. It is up to you whether to live in the house through construction.  Your home will be a mess during construction, and there is always some amount of dust that gets around the plastic walls and duct filters that your contractor should use.  Your contractor should be able to time the utility shutoffs for brief periods so that you still have power water, etc. when you need it.

4. Demolishing a portion of your foundation is routine, and not a reason to question whether to do the project.  However, it is always easier and cheaper, if possible, to design new spaces as distinct from old spaces, rater than trying to create large rooms that are "half-in/half-out".  That is, it would probably be better, if you can, to cut a door (6' to 8'?) in your basement wall rather than removing the whole 28 feet.

5. There are always pros and cons.  Homes take a lot of resources to build, maintain, heat, cool, clean, etc.  This means using natural resources, energy, and your money.  A larger house means a smaller yard.  All this said, a well-designed addition can completely transform the feel of your home and satisfy diverse needs.  Certainly you should talk with several designers before deciding whether and how to proceed.

Good luck with your project.  -Ted