Home expansion construction... No idea where to start.

[mfree]

Well, I've decided that the way to go with my house is simply to double it's size Actually, it's not a bad plan I've got... add another 40x40' wing to a house that's "cozy" in order to (a) have room for a REAL garage and extra bedrooms, and (b) allow somewhere to live while I completely rip apart the existing house and renovate it. What I've got now is 30x40' with a smaller furnished basement that needs some lovin' to be liveable area...

...anyhow, the method of construction isn't that important to me with the stipulation that I'd like this to be completely open area if it can be helped. The "garage" will be the basement and roughly 90% below grade, then a standard floor that matches with the existing house, and I'd like to have a useable loft space.

Of course I realize that with that much additional space I need to provide it's own heating and cooling, probably with another 3 ton central air/gas furnace stack. But that comes later in the plans.

Where does one begin with a project like this? All I really want is the general construction, the "roughing in" done... everything else I can complete on my own time once the garage/workshop is established and I've got room to work with. That's partially why I want the floorspace open... that'll greatly help with the shop area, and will let me sit back and ponder what the best way to integrate the extra space with the existing house is.

[meinbruder]

Where to begin?  The idea is the beginning; planning, design, and code acceptance are the next steps.  Draw up a floor plan and walk it into the nearest lumber company which offers TrussJoist, or similar, framing.  They should be able to generate a framing plan using a TJ ceiling and simple truss roof.  Youll need a bearing wall to provide for a usable loft but the rest of the floor space should be relatively open.  Building codes will not allow it as livable space until complete, inside and out; at least where I live; check your local building department for their interpretation.  If you hire a contractor, he(she?) should be able to advise you.

You might not be able to get a permit until submitting a complete plan for the addition and renovation of the existing structure.  Have a look at this website for the specs on one product and start pondering.      http://www.razortruss.com/beams.htm 
}:)>

[Leatherneck]

Yeah, that's the general approach: concept, then general plan, then detailed plan to submit to the code authority for a permit(s). They MAY require sign-off by a professional engineer or architect.

Many builders will generate the needed plans and pull the permits (land distrubance, building, mechanical, electric, plumbing, etc) for a fee. I'd solicit at least two, preferably three competing builders for the work.

You'll need to decide whether to run an electric sub-panel off existing service (commonly 200 amp) or install an entirely independent second system with a second meter.

There may be issues regarding well and septic expansion, if applicable. HTH.

TC

[Matthew Carberry]

And don't forget the financing.

Asssuming you don't have a coffee can of cash in the backyard (remember to move those before breaking ground) once you get a good estimate you can look into a home improvement loan or taking out a second mortgage.

I would avoid a home equity line in any event, think of them as a big credit card with a variable rate.  If you were buying something you could pay off in a few months, no big deal, but maxing out a HELOC is like maxing out a huge credit card, it's just dumb.  Go for a closed-end second or fixed-rate home improvement loan, actual fixed rate and term second mortgages.  If the cost is less than or close to $25,000 look at the FHA Title 1 loan.  The interest rates are better.

[280plus]

And please, for the love of God, get a heating and cooling guy in there right at the beginning, don't figure you'll build the thing and THEN figure out how you're going to heat it, that's just wrong... 

I STRONGLY suggest you look at heating the slab.

[mfree]

"You'll need to decide whether to run an electric sub-panel off existing service (commonly 200 amp) or install an entirely independent second system with a second meter."

Well, that's somewhat complicated. The existing panel is right where I'd want to cut the wall of the existing home for entry into the new space   I do also want 240v and perhaps three-phase in the workshop, since part of the plan to have all that room is to snag a few used machine tools.

So what I'm seeing here is:
1. Get my head centered on exactly what I want
2. Find someone to draw it up
3. Find a builder who'll do it
4. Find financing (mortgage/improvement loan)
5. Sit back and watch the work happen

Close?

As for "free space" I was thinking if I needed to have supports in the middle what I'd do is make a "stack", take 4' by 4' or 4x5 right in the middle and use that "room" on the workshop and living floor as a supporting wall; I'd use it for space for the water heater and HVAC, with venting running upwards within. Part of the expansion project is also to provide for the complete replacement of the plumbing and sewer lines in the old house by having new connections made in the new section and extending from there in the remodel of the old section. The old house's plumbing is all around 55 years old and is in poor shape.

As for heat itself, I was pretty much going to stick with gas fired, but I do suppose I have the option of floor heat. The workshop could be passive, for all I'm concerned... but if I'm going to fluid heat the floor upstairs I may as well do it for the basement. Total new area would be roughly 3920 square feet or 40,100 cubic feet. I've got a 3.5 ton 92% unit now (can't remember BTU) for the existing ~1900sq.ft. and IIRC that was oversized because of some insulation issues, so some may bleed over... I've just about smacked into my knowledge limitations there, don't know what the R value will be, depends on the construction method. If I can find somebody to do it and can afford it I'd like to use SIP panels everywhere I can, so there'll be 10' of block below grade, 2' above, 8' of SIP, then the roof on a 5/12 pitch...

Code may be pesky; one I'm concerned about is street entrances since I'm on a corner lot. The easiest way to have the entrance to the new workshop is to have it run in off the side street (note: will need retaining walls) but I already have an entrance on the front street... I don't know how the city will handle the short time in my plan where there'd be two sewer connections, two water line connections, etc.

This is such a huge project...

[280plus]

I just saw a gas fired water heater made by Rinnai that hangs on the wall and pumps out 180,000 btuh instantaneous. It is $650 wholesale so it wouldn't be more than oh, $1400 retail if I was going to sell it. I don't know what my competiors would do. But it's a lot of heat for small money compared to most. I believe you can dial it down on the temp too because you shouldn't need more than 140*F water if you do the floors right, maybe even less. It can also be used for domestic hot water but you'd have to get a separate one to do that. You can't mix heat water and potable water. The AC is a whole different story but if you're going to have AC and ductwork it's not a bad idea to include a hot water coil in the air handler and use that to supplement the floors. That way you can humidify too.

[mfree]

Yeah, AC and ductwork... the idea of the central stack is so I can have a supply and return vertical in the stack and have little branch stubs with single vents, that way I can "tune" so I've got equal flow from all vents either by baffle or by duct size. Keeps the ductwork to a minimum, less to clean, less drag for the blower to work against.

It'll beat the heck out of the spaghetti ductwork that I've got now.

The Rinnai boiler is tempting... Something I'll have to watch for with the slab though is making sure I don't produce weak points with having the tubing under the surface. My initial sketches have a 12' ceiling in the workshop so I could later on install a hydraulic lift (with a thick reinforced slab).

[Brad Johnson]

Be very careful going with a home equity loan (HELOC).  If your state is like Texas you have to waive your homestead rights to get a home equity loan.  This gets into all kinds of financial pitfalls, not the least of which is you lose your homestead exemption on your taxes (if you have one) along with bankruptcy protection for your homesteaded residence (should you ever need it).

A better way is a refi that cashes out enough to pay for the construction.  Talk to your mortgage company and see if they offer such a critter.  If not, there are plenty of places that do.  They vary in application, but the bottom line is that you are setting up a new home mortgage beginning that takes your current mortgage balance and rolls in the construction costs.

Brad

[280plus]

Yea, you should have at least 4" of concrete over the tube.

[Jamisjockey]

My advice:
Draw up your idea.  Find an architect to draw up blueprints from your idea.  Find a general contractor to take on the project. 
Sounds like quite the task, why not sell/buy?

[mfree]

Why not buy/sell? I like the property, I like the area... and it was really undervalued when I bought it. Add with that the smartfix 40 improvements and even in the lousy market now, prices should rise.

Even as run down as it is, I like this house. It *feels* good, as illogical as that sounds. I just miss having a workshop... and putting the workshop in where there's no big hill to get into it means subgrade, which means I can stack a floor on top of it, which leads to attaching that to the house, which opens up possibilities for remodeling, etc etc.

[Leatherneck]

I do also want 240v and perhaps three-phase in the workshop, since part of the plan to have all that room is to snag a few used machine tools.

OUCH! 3-phase is very expensive. As in lotsa bucks. Used tools powered by 3-phase motors can be found at auctions pretty cheap, because most home workshops can't afford the power. Replacement motors running on single phase 240V are about $100 per HP. Let the businesses and farms do the 3-phase.

FWIW, I made up a phase converter, but beyond the fun experimenting, it was just a pain in the groin. I eventually gave it up and bought a new single-phase motor for the saw.

Also, I second the motion for in-slab heat: it keeps a shop nice to work in, even when you have to open a rollup door briefly in the dead of winter. You can heat the tubes with whatever heat source you choose-gas, coal, oil, etc.

TC

[mfree]

How is 3-phase expensive, is it in implementation or billing? Because part of the whole idea behind the big workshop is that, before I die, I want to (a) build a car from the ground up, starting with a pile of DOM tubing, and (b) build my own sport aircraft. (B) doesn't require a lot of welding but (a) certainly does, and like yu said the cheap used equipment is mostly three phase. I also want shop equipment that's large enough to do machine work on engines.

[280plus]

I believe it depends on if it is available in your area. Commercial areas will have it but straight residential may not, so you would have to have the third leg pulled in if you really wanted it and I doubt that would be cheap. 

[mfree]

Hrmm. That is a good question... I'm not very far from an industrial area (~200 yards from a warehouse with rail access, other businesses), but I'm willing to bet that the power lines are as you said, not set up for three phase.

Darn.

Well, looks like I'll be hunting for a pile of 240v motors. But I still want some heavy amperage 240V service...

[Leatherneck]

Three-phase components are (unreasonably) expensive too, probably because they're viewed mostly as commercial use. When I built my workshop at home, the electric co-op was happy to install separate 240V, single phase 200-amp service with a new meter. I'm sure their cost has been paid back many times over in the 12 years I've had the shop. The 240V, 200 amp service has never even been strained by a large number of tools, heat pump, and 10 hp compressor, plus welders. Thin for a minute: haw many tools can you use at one time?

One thing I did that has been a joy is I put quad 20-amp outlets every 4" around the shop at workbench height. Thaty way, I seldom need an extension cord.

And if you'll be doing woodworking, plan for a dust collection system.

The air compressor is in the half-basement, because when it kicks in, it's LOUD.

150-psi air pressure is piped around the shop using black pipe; I don't know how people live without HP air:
tire inflation
air tools
dust/dirt removal from projects and clothing
"blow-drying" wet dogs (they love it, after training them)

TC

[280plus]

Good point on the dust collection. I went to a house with a basement workshop and a gas furnace and found the sawdust had been getting sucked up into the firebox by the draft and literally choked the burners down. How he never blew himself up with a dust explosion while working down there I don't know.

[Baba Louie]

Don't know about there... but here in Las Vegas anything over 600 sq.ft. requires a whole lot of action before construction.
Soils report by Geo Tech Engineer
Site Plan w/ grades/topo and boundary by Civil Engineer/Surveyor
Foundation/Basement Plan from Structural Engineer (S.E.) (they'll need to see final soils report)
Floor and Roof Framing plan by S.E. A 40' clear span is going to be expensive, so plan on some type of centered intermediate beam/column in basement to cut that 40' span down to 2 - 20' spans for the floor framing above (unless you want really deep floor trusses).
Our building code (IBC/IRC) requires a 1-hr fire resistive separation assembly between garage and residence (stairwell walls/door and basement/garage ceiling will be affected most likely). Typically 5/8" Type 'X' gypsum bd. taped and sealed does the trick, but anything that penetrates that assembly (HVAC duct & chases) will need some 1-hour dampners/sealants, etc.

Before you do any of that however, take a sketch of your idea showing proposed new addition attached to existing home to County/City Planning/Zoning to make certain of setbacks (assuming city size lot, not applicable on bigger lots), easements, etc. Once they approve the concept and tell you how many hurdles you have to leap to keep them happy, do the above engineering planning.

Plumbing, HVAC and Electrical should be thought out and might require some design coordination as well.

Talk to a Contractor (or two) and your bank for $$ figures and schedule of construction/payments.

Get final copies of engineering calcs & plans, get thee a permit.

Adding a new basement loaded with new structure above next to an existing structure will cause some settlement issues... be forewarned. Separation by dogtrot carport or breezeway can be a good thing in some regards.

Have fun building.