Need Experienced Advice on Upcoming Addition
Hi hope everyone is doing well. At a crossroads for upcoming addition, have a good architect in place with plans but need to pick an option. Looking for anyone who has experience or has been through a large project to give honest advice. So basically my 2 options would be:
1. Extending the 2nd story on rear of my house on posts over a first floor deck. So basically my 14×20 deck would become a covered deck. I would gain 2 9×14 kids rooms. Essentially what I need without requiring any major digging and much changing to original structure.
2. Building an attached garage 18×24 on side of house which would gain me 2 14×11 kids rooms on second floor. A 10 foot wider kitchen/dining area and a bigger back yard. I currently have a 24×20 detached garage in rear yard so I would be tearing that down and building the new attached garage. This would also require ripping up my driveway, as well as building a new foundation wall to support garage and floor above. Of course widening house would also require blowing out an outside wall as well as other interior changes. Not to mention installing new dry wells. The deck would remain a normal open deck.
A new attached garage would be a much better outcome but it is worth the extra expense and unknown costs? I could also go with option 1 and still remove the old detached garage. I could build a smaller detached garage further up the property and save the extra yard space. Currently my detached garage takes up half of my rear backyard. I have contractors pricing this out but I would be surprised if option 2 wasn’t substantially more expensive. On top of that would my taxes increase more with the additional square footage. Don’t want to price myself out of home over wants more than needs.
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Replies
My opinion just say no.
Don’t live in a construction zone.
Don’t add do the addition! House additions generally look like a sore thumb on what was a classic house.
If you do the math, you will find the number never work. Sell it with fresh paint price + construction costs are always more than the post addition sales price. Yes, I am calling every DIY TV show out as total BS.
I understand you want to keep your 2% mortgage. Just learn to love with what you bought.
Walta
I see your point, it def won’t add up for resale. Yes and all the tv shows are bs, but most reality shows are. I don’t want to move though or sell. I guess I should do whatever has the least amount of changes or overall costs.
I really don't like the idea of adding on above a deck. Most decks are barely strong enough to support themselves, let alone a structure above.
Architect explained it as new posts from the ground up. I’m assuming the deck is there but not actually supporting the structure above.
In 31 years, I've only found 3 decks that were constructed well enough to become supporting bases for anything but a deck in and of itself. That said, 2 of those were rightfully (and hotly) contested as a base by the local building authorities until I provided empirical proof of efficacy. I defer to the previous comments on this one. Start from the ground up if you choose to proceed, but be careful on your choices if you want to avoid spending more than you'll get out of the project in the long term.
What do you mean exactly by start from the ground up? Are you referring to posts from ground up or a foundation wall? I’m confused as to why an experienced architect would suggest something that wouldn’t work or support the structure above. I would think suspending an addition on posts would be more cost effective. Aren’t bridges and post and beam construction used in tons of structures. I could see if you slopped on a room over a wood deck. I believe in this case posts are installed in ground going up to the addition. The existing deck is not supporting the weight above.
Architects are not engineers. When the structure deviates too far from the norm, you really want a structural engineer involved. Large commercial buildings, for example, have architects designing the floor plans and facades, but structural engineers designing the frame.
In your case, the only way I'd feel safe with this would be to use steel support columns and a steel frame for the upper level, then wood framing built on that. Each supporting steel column would need to be on a concrete pier going down to frost depth. This type of structure avoids most of the problems you'd have with a wood framed open air type of first floor like this. Steel has significant advantages when used in projects where there isn't a lot of lateral bracing such as you're likely to have here.
I do think that if you want to make an extreme amount of changes to what you're starting with, it might just be better to raze the site and just build everything new. It's actually often cheaper to do things this way for a very large "renovation" project. I've seen commercial retrofit problems that ended up being similar in price to just building new, for example. Big retrofits almost always run into unforseen problems that drive up costs and push the timeline out.
Bill
Bill
Yes an engineer will look it over. Hard to tell but is the complexity of framing it this way going to cost me the same as just building a traditional foundation wall. You mentioned extreme changes worth to start new. Besides framing it to support the upper floor, this would cause the least amount of changes overall. I would only be adding on to the original footprint, not much site change or digging.
I’m no expert and I guess I don’t know much about structures or engineering but with a second floor deck I don’t understand why you couldn’t dig out the patio underneath the deck, build a box foundation with cement block and then drop the wood deck on top of that. The ceiling in my basement is open and that is all I see. I have a cement wall and the sill is wood sitting on top of cement wall. It can’t be done because no one mentioned it, I just want to learn why so I understand it better.
You don't want frost heave, which is when the ground essentially moves as it freezes and thaws, to cause stresses on your structure than can break it apart. Under your foundation wall, you have a footer down below the frost line, and typically some drainage around that footer. This is all there to help make sure the footer, and the foundation wall on top of it, don't move around over time. The structure built on top of the foundation relies on the underlying foundation to support everything.
If you excavate down and build a "real" foundation, then you'd probably be OK, but you seem to be talking about building up above a deck or patio, presumably using the existing supports. Patios are typically just relatively thin concrete slabs, decks are oven built using simple buried posts or blocks. This isn't the same as a proper foundation, and won't be nearly as stable over time.
I think that is what you were asking about here.
Bill