I have a tiny bungalow (20' wide by 25' deep) and am thinking about planning a second floor addition (and an attic room above that perhaps). There are no studs in the current walls (as I found out when redoing the bathroom). It looks like its a double thickness of brick on top of cinder block foundation with footings (built in Toronto circa 1948).
We don't really have the option of moving out while this happens so what I'm thinking is this:
1. Remove roof, insulation, wiring etc to expose ceiling joists
2. "sister" new joists to existing 2x8 that hold up ceiling
3. install plywood floor
4. build new 2nd floor walls
5. build new roof
6. cut hole in current ceiling and install stairs to 2nd floor
My 2 main questions are:
1. Is it possible (at reasonable cost considering the scope of the project) to span the 20' width of house (wood I-beams?) so that all walls on main floor could come down?
2. How is the addition held down? Is it enough that new joists are nailed/screwed/glued??? to existing joists or does the new floor need to be bolted down into the brick walls? I don't even have the right terms to properly pose this question, but I hope it makes sense. I have no idea how the current roof is fixed to the walls.
What you propose is possible, but difficult to live in during. Keeping the finished first floor dried in is difficult to achieve efficiently. Plan on relocating from room to room during the construction phase. You will need a good set of plans and an experienced contractor to pull this off. Definitely not a DIY project. Good luck with the addition.
I'm in the middle of a 2-story addition right now....to the back of my house. We only lost one bedroom while we are doing the construction....but like six said....it's an issue when your living in the house....
I think your underestimating the scope of work. One of the big issues is your foundation....you are going to have to underpin your existing foundation to hold the second floor. Your also most likely going to have to open up every wall and install posts to support the second floor.
Your going to need engineering....lots of it....
It helps to know where your living....if your bungalow was in Pasadena California....I'm pretty sure you would not be allowed to add a second story....
To get an idea of the work...click on the link in my signature...
I have seen contractors who install a 2x4 bottom plate on the top of the existing ceiling joists around the perimeter of the proposed addition. Then they install new floor joists for the second floor to bear on the added 2x4 plate. This is faster, less labor intensive, and reduces the amount of modifications you may need to make to the electrical conduits located on the existing ceiling joists. The down-side is that it adds some height (including number of stair risers) to the addition.
You need to have an engineer tell you how to modify the foundations and anchor the second floor to the first floor.
Your suggestion isn't something that would have occured to me, interesting. You are right about the height though, and my stairs will likely be a little cramped as it is.
Thanks ddawg16
I think your underestimating the scope of work. One of the big issues is your foundation....you are going to have to underpin your existing foundation to hold the second floor. Your also most likely going to have to open up every wall and install posts to support the second floor.
This project will only happen if/when I get an engineer to confirm that my existing foundation is adequate (I'm not ripping up a perfectly finished basement to add 2nd story).
Walls will have to open up to insulate anyways, but I don't understand why a solid brick wall couldn't support a second floor? Could you elaborate.
Your blog has convinced me not even to think about cantilevering for extra space. Yikes!
Sixeightten - the DIY component is the preplanning and then the final painting. This certainly isn't a job I will be doing, but I like to know what's going on before I begin talking options with architect or engineer.
I did exactly this about 12yrs ago on a wood framed house. When I inquired about clear spanning the first floor with I joists......the cost to go from 9 1/4 to 14 inch joists was amazingly steep!!! I did do a 4 sided cantilever so that did add considerable cost when upsizing as well. If my memory is correct cantilevering actually added the amount of clear span.....something about changing the load because the walls of the second floor would actually push the center of the spans up.
This is the sort of thing that is very helpful for me in wrapping my head around how things will work (or IF they will work) before real planning begins.
What is the alternative to 20' I-joists? Would a large glue-lam (is that term right) that spans 20' in the middle leaving spans between it and the front/back of the house of 13 feet work. Can 2x12s span 13'? Note, the main floor creaks. I want to avoid a creaky 2nd floor like you wouldn't believe.
ive also done an addition as house engineer describes.. by doing it this way seperates teh floor system for the 2nd story from the lower ceiling so there is no chance of the ceiling sagging. it also reduces the amount of dust that the homeowner has to deal with.
the key thing is to have a very experience crew who are not only highly skilled but very efficient. the one i worked on we had the roof cut off in the morning and the floor joists in place that evening with the sheathing started. 2nd day the floor was sheathed and we had 2 walls stood, 3rd day all exterior walls were up and straightened. with back framing started. 4th day the trusses were stood and sheathed. 5th day the shingles were on and we started to install windows. the key thing is to tarp over the entire house at the end of every day to keep water out
Brings back memories!!
Every night we spread 4 20x20 tarps.....
I built temp walls in my living room to "save" the ceiling.....dropped my Stihl TS400 thru onto the kitchen table the first day.......put my foot thru the hall ceiling another day.....
We ended up gutting the first floor the next spring!!!!
Definitely a learning experience....I was 25 I think.
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