20 x 30 1 1/2 questions

Started by hhbartlett, May 26, 2012, 12:49:00 PM

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hhbartlett

So, after much going back and forth, I think in the end we're going to build the 20 x 30 1 1/2... sort of. Or really it's the 20 x 30 single storey with a true 1/2 storey on top.

Here's what I'm thinking, please blow holes in my plan if possible.

For foundation, we're going with a FPSF concrete slab. Not going to bother with in-floor radiant, and we plan to stain and finish the concrete instead of laying more flooring on it.

For the first floor, it's pretty much exactly what's in the 1 1/2 storey 20 x 30 plan.

However, the second floor is where I'm considering a modification. Instead of balloon framing and then a loft, I'm thinking we just put on another full floor platform on the 8' (not 10') wall of the first floor, then build a 12/12 pitch roof right on the platform, like an A-frame. I basically want two 12' x 12' room upstairs with cubby hole storage along the long walls. Additionally I'm considering a 2 dormers in the middle of the long walls, one on each side.

Crude drawing of what I mean:


My reason for this design is, it provides 2 good sized bedrooms and a second bathroom for my 2 girls, there's lots of storage (albeit in a triangular space), it should be easy & cheap to build, and this would make the house really close in design to many other houses in our area that were built 100 years ago.

My question is, should I go with the 20 x 30 1 1/2 plans, or just the single storey plans and modify them? My issue is going to be a plan for supporting a full floor across the 20' span. I figure by not balloon framing and putting a proper second floor on it should be easier than sistering in jack studs and stuff; this way I can just use i-beams on top of the regular walls, like building any other 2 storey house, but going right to roof construction instead of walls. It should be cheap and easy to build this way I'm hoping. This is also what I understand to be a proper 1 1/2 story house.

Does anyone see any problems with this approach?

John Raabe

You will want to tie the roof rafters to the floor joists to make a stable triangle of the roof framing. You can have a tie at the ceiling height (probably 7'-6"). Draw it out in section to see if you have enough headroom. You should probably use 2x10 or 2x12 rafters so you have decent insulation. If you have the single story plans you can work with that section and modify the pitch to 12:12.
None of us are as smart as all of us.


hhbartlett

Quote from: John Raabe on May 26, 2012, 01:29:44 PM
You will want to tie the roof rafters to the floor joists to make a stable triangle of the roof framing. You can have a tie at the ceiling height (probably 7'-6"). Draw it out in section to see if you have enough headroom. You should probably use 2x10 or 2x12 rafters so you have decent insulation. If you have the single story plans you can work with that section and modify the pitch to 12:12.

OK, this is sort of the cross section of one of the bedrooms, I think it will work fine:



Measurements are a little rough of course. I was thinking 2 x 12 rafters, should be good and strong tied to the floor joists too.

One thing I see now that's an issue is the placement of the stairs in relation to the door. Also, on both the single & 1 1/2 plans, I notice there's only one exterior door? I didn't know you could do that. I'd probably replace one of the dining room windows with another door, maybe a patio door of some sort.

mgramann

Out of curiosity, why no radiant heat?  In my opinion, they are one of the best space saving systems, and pretty easy to DIY.  It would work great with the concrete floor.  I speak from experiece, it is the same combo we have at our cabin!

hhbartlett

Quote from: mgramann on May 26, 2012, 08:27:16 PM
Out of curiosity, why no radiant heat?  In my opinion, they are one of the best space saving systems, and pretty easy to DIY.  It would work great with the concrete floor.  I speak from experiece, it is the same combo we have at our cabin!

We've been tossing that one back and forth. In the end, it's one more thing to add that I'm not sure we need. If the house was bigger I'd probably put it in but we're only talking about 600 square feet of slab here. The wood stove should be more than enough, and I'm looking at a small air conditioner / heat pump unit as well for spring/summer/fall. Down the road, if I had to fix anything in the slab, I won't have to worry about jack hammering through the heating pipes in the floor. We might however put radiant floor heating in the bathroom downstairs in the form of an electric mat, if we tile the floor.

Of course, we might change our minds and at least put the pipes in anyway for all that they cost.


mgramann

A woodstove should be more than enough, and is what we use primarily.  We use the floor heat to keep the temp at 45deg. while we are away, so we don't need to drain the pipes every time we leave.  Of course, we are there almost every weekend, so that makes sense for us.

In our system, putting the pipes in was the most expensive part(we contracted out the shell/slab for our addition).  The stuff to make it work wasn't too bad at all.   I find that many "kits" are more complex than they need to be.  If one can sweat copper, they can build their own system for a fraction of the cost.  If you change your mind, let me know and I'll send pics/explain our system so you can price it out.

hhbartlett

Quote from: mgramann on May 27, 2012, 09:12:50 AM
A woodstove should be more than enough, and is what we use primarily.  We use the floor heat to keep the temp at 45deg. while we are away, so we don't need to drain the pipes every time we leave.  Of course, we are there almost every weekend, so that makes sense for us.

In our system, putting the pipes in was the most expensive part(we contracted out the shell/slab for our addition).  The stuff to make it work wasn't too bad at all.   I find that many "kits" are more complex than they need to be.  If one can sweat copper, they can build their own system for a fraction of the cost.  If you change your mind, let me know and I'll send pics/explain our system so you can price it out.

Why would you use copper? All the systems I've seen are pex, which is pretty cheap.

John Raabe

hh:

I think you cross section should work fine for the two bedrooms. Good diagram.

Here's my new favorite heating/cooling system. http://countryplans.com/smf/index.php?topic=11964.msg153818#msg153818
None of us are as smart as all of us.

hhbartlett

Quote from: John Raabe on May 27, 2012, 10:39:33 AM
hh:

I think you cross section should work fine for the two bedrooms. Good diagram.

Here's my new favorite heating/cooling system. http://countryplans.com/smf/index.php?topic=11964.msg153818#msg153818

Yes, that's what I mean; a mini-split system. Saw some 12000 btu units for $950 which is probably all we'd need.


mgramann

Quote from: hhbartlett on May 27, 2012, 09:15:59 AM
Why would you use copper? All the systems I've seen are pex, which is pretty cheap.

Sorry I didn't explain better.  Most of the system is pex, but some items such as the fill valves, air eliminator/pressure tank, and pump are connected with copper.

BADB0Y

When I build my old shop, i figured I'd go ahead and run the pex in it, just in case I decided later. I never did set it up, but it was what sold it when it was on the market. Not to mention a lot easier and cheaper than if you started having those hindsight revalations.
Please excuse my typos, I post from my cell phone 90% of the time!

Don_P

Same here in the house, the tubing is in the floor but not hooked up. We had a discussion about it, she had worked in greenhouses where they had thermally shocked and broken up the floors with bad wood boiler control and was not wanting it. But it was cheap enough that we stuck it in anyway. I've got several rolls of pex to put in the shop whenever I get around to a real floor. Really look forward to it there, my vehicles seem to pick the worst days to break down. It does complicate drilling into the floor for walls etc and the mini splits are nice.

It really pays to take the time to scale it tight and figure out the stairs ahead of time, checking headroom at the floor and to the roof, clearances, etc.

hhbartlett

This is a little off topic, but here's a question: if you had pex in the floor, could you not simply hook up a loop to your water heater with an inline pump, and have that pump operated by a regular wall thermostat? I've seen those hot water pumps for around $70. The return water would go into a T on the cold water feed side of the water heater. I'm thinking this would work better with a tank as opposed to a tankless system. Seems like a cheap and easy solution.

mgramann

#13
What you describe is referred to as an open loop system.  The advantage is only one heater and pressure tank are needed.  A few disadvantages are that if the floor system was running awhile, your hot water supply could be depleted, making for a cool shower.  The second is that if you are going away, and plan to shut down the heat, the water in the slab could freeze if you don't empty the system.

I prefer the closed loop system filled with antifreeze using a small water heater.  We have a 15 gallon electric unit with an oversized element.  The thermostat is connected to a relay, which turns on the circulation pump.  The heater element turns on automatically as needed in the water heater.  No worry of overheating the slab, no expensive boiler.  In summer, I turn off the water heater, and in winter, power it back up.

I'm posting from my phone, so I apologize for any typos.


redbird

This is exactly what I want to do, except I want the stair to be like what's in the Universal cottage plans.

Have you started building yet?  I'd love to watch your build and I'm sure it will be just like ours (in the future :)

Also I was hoping to skip the dormer on the non-bathroom side, but not sure about height and stairs and all that.  If the pitch is high enough it doesn't seem like it would be a problem.
"Any fool can make something complicated. It takes a genius to make it simple."
― Woody Guthrie