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Discussion Starter · #1 ·
Hello,

I have a small 1.5 story cape cod I want to remodel. The ceiling joists are 2x6s that run a span of 12.5 feet, and 14 feet. Now I've been searching the span charts and according to the charts,I see that at 12" OC the average span allowed for 2x6s is around 9'. So my questions are, if I sister the existing joists with another 2x6 and add more so they are 8" OC, will that be strong enough support for a full upstairs? Or do I have to use 2x8s or 2x10s? My long term goal is to raise the slanted roof and have 3 bedrooms and a bath upstairs. There are currently 2 bedrooms upstairs already. And what if I could do 4" OC, would that make a difference? When I go up there, the floor seems very sturdy and there is no bouncing that I notice. Thanks
 

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Kind of confused me but I think I know where you are headed.

My immediate red flag concern was whether your current bearing walls are up to the addition you have in mind.

Anyhow, if you really are planning an addition to the top of this thing I would suggest glue lam beams or maybe even steel. With either you can span just about anything and even pull your top walls in with steel plates noone will see. If this is historic masonory construction though, I would not even dream of adding the weight of what you have in mind to the brick bearing walls.

I know this is a DIY site but faced with a challenge like this, I would have one of the architects or structural engineers I work with on the phone if it were my project. Mine are not outrageously expensive.

You are definitely going to need some nice drawings for permit approval for this anyhow so why not get on with it all. Architects are good at what they do and have saved me tons of money I would have wasted thinking I knew what I was doing.
 

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And, what is going to support all of this in the ground? Do you have proper footers, etc? No doubt about it; engineer time.
 

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Discussion Starter · #4 ·
Yeah I just called an engineer. I'm waiting for a call back. I think at the very least, I could build dormers upstairs. Most of the homes in my neighborhood are cape cods with raised roofs upstairs, and I'm assuming they were built with the same materials. I have no problem with tearing up the floor upstairs and putting in a new floor system. I think my fopundation would be strong enough. Theres already 2 bedrooms upstairs, all I'd really be adding is a bathroom. We'll see what the engineer says. Do you know what they cost on average btw?
 

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Yeah I just called an engineer. I'm waiting for a call back. I think at the very least, I could build dormers upstairs. Most of the homes in my neighborhood are cape cods with raised roofs upstairs, and I'm assuming they were built with the same materials. I have no problem with tearing up the floor upstairs and putting in a new floor system. I think my fopundation would be strong enough. Theres already 2 bedrooms upstairs, all I'd really be adding is a bathroom. We'll see what the engineer says. Do you know what they cost on average btw?
Costs vary by region, and even within a market, costs can vary widely. I know what I would charge ($800 or so depending on how far away you were). It would include a structural inspection of current conditions, calcs, letter, framing plan, etc.
 

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And, what is going to support all of this in the ground? Do you have proper footers, etc? No doubt about it; engineer time.
Great point I forgot in my posting. In addition to bearing walls that can handle this, your foundation needs to be solid.

Again, architect and/or egineer time. Trust me, if you have never worked with one before? You will end up loving the experience and you might gain from their insight. Mine can draw and get drawings past building permit idiots in seconds. Inspectors seldom challenge their drawings but just annoy me for the usual stuff. Posturing and horseplay but I have never had a project halted or stalled.

And do not be casual about thinking you would only be adding a bath upstairs. Do you know what tubs weigh even before you fill them with water?
 
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