How to Build a Second Story Addition – Outdoor Home and Garden

Building a second story addition can beavery rewarding but alsoextremely challenging experience. How do I know? I have actively participated in the process of our own full second story addition. I worked on virtually every aspect of our project from the initial planning stages to the very end. I designed it, worked full-time on the crew and lived in itwhile it was being constructed.

I am sure there are several strategies of how to go about buildinga second story addition, but this is the story of how we did it. While describing everything, I will try my best to keepit brief yet informative. If you are considering this type of addition, you may pick up some tips and guidelines for what to do and what not to do. I know that I learned a lot about how to do a second story additionfrom others online before we began ours, so I hope this experience will helpothers with their project.

We started with a 2 bedroom 1 bath home on a basement that was about 90+ years old. We wanted to upgrade it to a 5 bedroom 3 bath home. We took one of the main level bedrooms and convertedthat into the new staircase area which also had room left over for a small office. Fortunately for us the house was built very strong and has been well maintained over the years which made this project possible.

Before you begin, it is important to understand if your existing home is even capable of supportinga second story addition. Along with speaking tocontractors about whether or not they think it is structurally possible, you may want or needto consult a structural engineer or architect in your area to determine if it isadvisable or not. Often the municipality in whichyou live will require an engineer or architectsstamp of approval on the projectanyway in order to obtain a permit. These professionals will be able to tell you whether or notyour current foundation can support the extra load as well as what improvements may need to be made such as installing extra supports, beams or other considerations in either the foundation area, the main level or both. They will probably also consider the spacing and material type of the existing wall framing as well as existing window and door header beams.

In our case, we underestimated how much it would cost. It ended up being around $80 per square feet to add up which is veryreasonable to me. That is with me working on the crewmyself full time and receiving no pay to do so. Therefore, if a homeowner had to hire that extra crew member to build it, it could add substantially more onto the project. Depending on where you live, I would suppose it could easily go to $100 per square foot or moreif everything was done for you by a contractor in a top notch fashion.

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I have experience and education in design so itwas fun for me to design the plans, the interior layout and the exterior. However, I realize that most people may not be able to do that or even want to. In that case, hiring an architect to design the project for you or to consult may cost you extra money but may be well-worth it in the long run. As far as design goes, my overall goal was to make the new addition match the architectural style of the existing part of the house and make it appear as ifhad always been there. One unique feature we utilized to help tie it all together was to create a faux roof overhang in the front, back and sides that helpedto replicate the look of the second story being a full-length shed dormer.Also, consider the fact that not only will you be designing the new addition layout but also most likely the first level will change due to the need to install a staircase. We chose to build a U-shaped staircase which turned out really well. In our case, to build the staircase, we also had to remove a load bearing wall. Therefore,prior to the second floor construction, we made sure that we had an adequate beam in place to carry the load of the second story where we took out the load bearing wall on the first floor. We used two LVL beams fastened together which worked very well. There are charts available to determine how many and what size of LVLbeams you will need in order to span certain distances.

We solicited a few bids from contractors in each of the specialties that we needed. In our case we needed to work with the main carpenter builder who helped do the structural upgrades in the basement and main level, the demolition and the framing and new construction. We also worked with an electrician, plumber and heating and air conditioning contractor. One special consideration is that the electrical hook-up to your house will most likely need to be temporarily relocated. The electrician and power companyinstalled ours on a telephone pole near the house so that we could work more safely. I coordinated all of these contractors so in a way, we acted as the general contractor which saved us even more money.

One thing to factor in is how much extra time it takes to do everything on a second level. Almost all of your removal, labor and new materials will be at leastten feet or more off of the ground which involves considerably more time and effort than working on a single story level. Our project took over 6 months from start to completion which is also longer than both we and the contractors thought it would take. We were slowed down because we were working with a small crew and also by weather because it was a very rainy Spring. I would suppose that under ideal conditions and with a larger experienced crew, it should be able to be done fasterthan we did it.

In order to do a project like this, the home must be protected from the inevitable rain that will happen. We had to have part of the roof off for a long period of time which did lead to some leaks. After some trial and error of piecing fourlarge tarps together, I found that having double protection was the best way to go. What I mean by that is that we had the fourlarge tarps pieced together and then onegigantic tarp covering the entire thing. That strategy worked very well actually.

This part can get a little technical, but Ill do my best to explain what we did. In manycases, the attic floor joists, which would be the first floor ceiling joists, are undersized and not suitable in strength for a new floor. In our case we only had 24 ceiling joists in our attic when we actually needed at least 28s. After determining some calculations for floor strength, we ended up going with new 210 floorjoists that we sistered(joined) in the middle above the main load bearing wall of our house. We could have done with TJIs which are engineered I-joists that are very strong and can span great distances. However we chose to stick with dimensional lumber and it worked out pretty well.

Now for simplicity we wanted to keep the first floor ceiling in place and so the 24 ceiling joists had to stay. We found a solution to basically raise the new floor above the existing ceiling so that the existing ceiling and new floor would be independent of each other. We added a stack of two24 lumber blocking on top ofthe outside perimeter walls of the house that rested on the top plate of the first floor wall. We thenattached the new2xend plates to the blocking and then using joist hangers, hung the new 210 floor joists from the end plates. A similar strategy is explained by a contractor in this helpful YouTube video. (link)

While it was very challenging at times, we were able to keep most of the old roof on for weather protection by providing support for the tarps while we build the new second story floor. Basically it involves removing a few feet of roof sheeting and shingles all the way around the perimeter of the roof so that you can install the new floor beams in between the existing rafters or trusses. It was a slower way to do it, but we felt safer all around for better weather protection. I do not have a good picture of this step exactly but I found this strategy in thisold Popular Mechanics article which begins on page 164, where it isdetailed and illustrated in further detail.

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When we had done all we could do underneath the protection of the partial roof, we looked for a few days of good weather. Then we deconstructed the remaining part of the roof and disposed of it. We then had the new 3/4 T&G obsflooring delivered via crane and installed that on top of the new floor joists. One tip I might recommend is to make sure you are able to remove the osbin the area where the plumber is going to work until they are done. They will certainly need access to the sub-floor at this point to do their connections and you can glue it down in that area once they have completed their part. Once the sub-floor was on, we secured twoheavy duty tarps that covered the whole floor for weather protection while we were building the walls. Once the wall framing, trusses, windows and all sheeting was on, which protected us from the elements, we were able to cut away the tarps revealing our sub-floor once again.

It was very important to nothave the house appear top-heavy so I did not want the outside walls to be too tall. It think the outside walls are around 79 tall. In order to increase the ceiling height inside, we utilized scissor trusses which created cathedral ceilings. While it did create more work on the interior framing, we were very happy with this result and creates a lot of room in the ceiling. I believe thatit is around 96 at the peak inside. In this case you will not have an attic and all utilities including duct work will have to fit in between the webbing of the trusses which can be slightly challenging but for the heating and air conditioning contractor.

Once wereached this point, other than having to re-build the chimney, it was basically like building normally and wedid not really have to have all of these special considerations of building on top of an existing structure. I am sure there are other things to consider but these are some of the main highlights and tips that I can recall. As you can tell, it is a VERY extensive project to tackle. If I am honest, I am not sure that I would recommend someone do it unless they REALLY love the house, neighborhood or location. It may be advantageous both financially and time-wise to just sell your existing home and buy what you want. But if you are like us and decide to take on a project like this, you can be very happy with the end result and benefitfrom the vast amount of practical building knowledge that you will gainduring the process.

While I hope this story educates the reader on how to build a second story, it needs to be made clear that I am not an architect, engineer or building contractor by trade. All of this is just first hand experience and advice. Consult professionals before attempting any projects of considerable size like this one.

What are your thoughts? Id be interested to hear from you. Feel free to leave a comment below!

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Ryan is the Senior Editor here at Outdoor Home and Garden. He has a degree in Horticulture and has worked in the field of Facilities Management for over 16 years.

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How to Build a Second Story Addition - Outdoor Home and Garden