adding a second level

[Jen]

I am working on adding a second level to my home, it is a split level home, so there already is a second level above the garage and family room, but I also want to add rooms above the kitchen, what special considerations should I make? Should I be concerned about the foundation? The house was built approximately 1990.

Thanks

[JWmHarmon]

The first step absolutely necessary is to determine if the footer and foundation can support the added load of the second story. If it is determined that the footing and foundation are not adequate, you may be able to dig outside the current foundation and pour a new footer and foundation wall. You may also take a different approach and install concrete pads instead of a full footer, with additional post built to take the load. You must have the necessary engineering work done to determine if this is feasible.

Next, if you are building on top of the existing wall, determine if it is built with standard framing techniques to make sure it will support a second storey. If not, it will need to either be rebuilt or reinforced to support the additional loads.

If you decide to remove the roof and continue with this project, make certain that the walls are properly braced as you remove the roof. Make sure that when it is rebuilt it has adequate fire stops installed between the first and second floor so there will not be any openings between floor that might act as a chimney in case of fire.

Pay special attention to flashing details between the new part and the older sections. You must prevent water damage where the two join. You will also have to determine if your current electrical service panel is adequate or if you will have to add a subpanel. Check with an electrician. You may also have to provide an additional heating/airconditioning unit or replace your current system.

I built such an addition onto a house that was built in the 1930's, adding a new wing and one section that created a second storey over one section of the original house. The additional living space was well worth the investment in that particular case.

You may also want to compare costs of doing this project or simply buying another house that is closer to what you want. Will the value of similar houses in the neighborhood allow you to recover some of the costs, or will it change the value to the point where it will be overpriced in the neighborhood, making it harder to sell eventually?

[miaq54]

Just surfing around, stumbled on this site. Looking for a general cost in adding a second level. I know there are many factors, including foundation and current structure. But do you have a site, or know from personal expierence generally what it would cost.

Thank you

[miaq54]

Oh ya define currency to, as I am in canada. I would also assume the location and contractor would factor in as well. Toronto, Vancouver would be different then Saskatoon LOL

Thanks Agaon

[JWmHarmon]

The cost of new home construction varies from city to city. If you scroll down in the data in the link below you will see that new construction costs are usually above $100 U.S. (about $130 Canadian) per square foot. I would assume that such data is available for cities in Canada.

http://www.sedcor.org/CL04.pdf

You will have additional costs when building over the top of an existing house. First will be the engineering costs to determine if the existing construction is adequate to support the new construction. I would recommend that a qualified person inspect your house to determine how best to meet the engineering requirements.

You will then have demolition costs to remove the roof. You may also have disposal costs of construction/demoltion debris. You will have to analyze that for your own area of Canada since there is such a wide range of disposal/recycling fees.

Your builder will have additional costs for bracing the current structure and protecting it from the weather while you have the roof removed. Your builder will have additional costs to connect the new part to the old part, with special attention to the flashing details. It is almost always more expensive to connect the new to the old than to build an all-new structure.

You will then have the cost of the new construction itself.

The best way to get an idea of how much this will cost is to contact a local design professional to determine the costs. Project costs for this type of addition will vary widely depending on how simple or how difficult it is.

Based on my experience I would tell you to immediately add 20% to the per square foot cost of new construction. This may not be enough for your area of Canada, but it will give you some idea of what you could expect to pay.

Have you considered adding a separate wing to your house with a connecting hallway? If you have space on your lot, this may be a reasonable alternative to building on top of the existing section of your house. The advantage is that the new construction is similar in cost to other new construction. You save demolition and disposal fees. You save money with the simpler connecting hallway as opposed to the removal of the roof. You save money by simpler flashing and weather protection.

Either way you need an on-site evaluation of the potential costs. It would be difficult to give specific advice over the internet.