Author Topic: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.  (Read 275 times)

0 Members and 1 Guest are viewing this topic.

Offline Rys

  • Junior Member
  • **
  • Posts: 92
  • Welcome to the CP-Forum
Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« on: October 07, 2017, 12:07:43 PM »
I've had my plans for some time now. Am now ready to build. My dilemma is I suck at computer stuff!  ???
Was wondering if anyone else has done this that could help me with plans? Staying with the same open concept as original plan. Want to add a shed dormer upstairs for more headroom on one side only. Would like to incorporate small open area at top of stairs for a reading loft. Build will be on a walk-out basement butted up into a hillside. Would also like to do a hallway exiting out the long end of the house through a mud room. Bedroom/pantry on one side, bath/laundry on the othe side. Any suggestions or help greatly appreciated!

Rys

Offline John Raabe

  • Administrator
  • Journeyman
  • *****
  • Posts: 5,547
  • Whidbey Island, WA
    • CountryPlans - About Us
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #1 on: October 13, 2017, 03:04:55 PM »
By going wider than the 20' width of your plans you will need to check with the lumber supplier to see what they can supply for joists. You might also check if they know of someone to help with modifying a stock plan as you will have a new layout too. Also, you will likely change the loft as it could have more headroom.
None of us are as smart as all of us.

Offline Rys

  • Junior Member
  • **
  • Posts: 92
  • Welcome to the CP-Forum
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #2 on: October 14, 2017, 02:27:10 PM »
HI John!
 That's kind of my problem, without hiring someone to completely redo things, I'm at a standstill.  ???
 I live in Podunk, USA. Not many resources here.
 I was trying to avoid getting an architect involved to save money, of which I am in short supply!  :)
 We were going with I joists for the floor and hopefully parallel chord? roof trusses. The floor plan will stay pretty much the same as the 20x30. I thought by using the I beam floor joists we could span the twenty four feet, keeping an open floor plan,except where the stairs come through? I'm assuming at least one if not two posts would have to run from the stair opening at the loft down to the basement and be supported by a poured footer?
Looking for someone in our group who has built something similar.
Any help is greatly appreciated!
Rys

Offline MountainDon

  • Administrator
  • Journeyman
  • *****
  • Posts: 16,508
  • Jemez Mountains, NM; that's pronounced HEY-mess
    • My 15.75 x 30 Jemez Cabin
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #3 on: October 14, 2017, 02:44:51 PM »
Length is easy to increase, width increases need engineers.  If you go with engineered floor and roof trusses, the truss company will do the engineering that is required. You need to provide them the width, one story vs 2 story, location or snow load... they'll know what details they need to engineer the trusses.  They will also provide the paperwork that will satisfy any building inspection departments, once you have paid them. So look around for a nearby manufacturer.
Just because something has been done and has not failed, doesn’t mean it is good design.

If you didn't have the time or money to do it right in the first place, when will you get the time and money to fix it?

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,084
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #4 on: October 14, 2017, 04:06:57 PM »
What are your building dept requirements for plan submission... or do you need to submit a set? Let's see what you have so far.

Offline Rys

  • Junior Member
  • **
  • Posts: 92
  • Welcome to the CP-Forum
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #5 on: October 14, 2017, 05:03:32 PM »
My building dept accepts hand done drawings. I was going to try and use the plan that I purchased here and make it wider and longer with the appropriate types of floor joists to span the extra width. Still going with the ten foot walls and partial loft area for an upstairs bedroom. Want to incorporate a small shed dormer to one side for better headroom and Windows.
With the added width I'd like to add a hallway out to the end of the house between the bedroom area and bathroom to act as our main entrance from the parking area.
 I would gladly pay someone from the boards to help with the modifications. They are just beyond my capabilities!

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,084
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #6 on: October 15, 2017, 08:29:24 AM »
I've spanned 24' with open web joists a couple of times. One client then went over the floor with another layer of subfloor with seams offset and screwed down and together well. That mass calmed down the snare drum effect those long spans can have. I went to an engineering training session and talked with an engineering professor. He had worked it out to annoying vibration frequencies and mass was one way he suggested to calm those floors down. Upshot of that is, those long spans do come at a serviceability cost. In the basement I'd accept a center line of posts supporting a girder and break the span of the main floor down to 12'.

Upstairs I would investigate attic trusses. If they are built cantilevered with a 2' overhang they are essentially at the same elevation as common rafters on a 2' kneewall. Typically they have the "wall" at 4-6' tall inside so on a 24' wide building the upper floor is 16-18' wide.

Well, no matter how it works you need to be able to receive drawings. Let's try something different. Download Sketchup and begin to familiarize yourself. For one thing learn to "save as" sketchup 2016... that is as far as my computer graphics can keep up. We can post snapshots of the screen for a plan but there is much more useable information there if you learn to rotate the 3d model on your screen and zoom in on a detail of interest. Being able to do that with a good drawing/ model during the build would hopefully be more pre-emptive than all of the "well you really should have done it this way"s.

Even a photo of a napkin with chicken scratches and dimensions is a start though...

Offline Rys

  • Junior Member
  • **
  • Posts: 92
  • Welcome to the CP-Forum
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #7 on: October 15, 2017, 12:11:37 PM »
Thanks for all the advice!  :)
Wish I could convince my husband that twent foot wide is plenty!
Will download sketch-up and see what I can do. I'm sure I'll have many more questions.
Rys. 

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,084
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #8 on: October 15, 2017, 07:38:15 PM »
While you are learning to crawl with sketchup go ahead and sketch what you know so far. With that rough hand sketch I can begin the sketchup model and post that for you to play with and take to the next level. Back and forth in an iterative fashion any number of people can input and try modifications to the sketch. As long as you keep a file when you start you can play to your hearts content and not risk "losing" anything.

I actually prefer at least 24' width, things seem to start clicking easier.

Offline Rys

  • Junior Member
  • **
  • Posts: 92
  • Welcome to the CP-Forum
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #9 on: October 16, 2017, 02:42:14 PM »
Will do. Thanks!

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,084
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #10 on: October 16, 2017, 05:05:34 PM »
It was too cold this morning for me and I wanted to play with this and Medeek's plugins. I certainly didn't do it expertly but trying to show the concept of what I'm thinking.



This is the sketchup file, you can download and save it. Open it in sketchup and you can manipulate it in 3d and draw on it.

http://timbertoolbox.com/cp/Rys1.skp

Offline Rys

  • Junior Member
  • **
  • Posts: 92
  • Welcome to the CP-Forum
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #11 on: October 17, 2017, 03:02:45 PM »
Thanks. Will do so when I'm at a computer.

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,084
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #12 on: Yesterday at 05:42:37 AM »
That works and keeps the floor clear, kind of cluttered and a marriage of components
Playing with the framing a little differently, stick framed roof with structural ridgebeam, dropped joists on tall walls, 2 interior posts. That was quick, the post locations and ridge loads would still need work.


File here;
http://timbertoolbox.com/cp/Rys1.1.skp

I could see potential for kicking out a dormer on the other side for stairs.

Offline Rys

  • Junior Member
  • **
  • Posts: 92
  • Welcome to the CP-Forum
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #13 on: Yesterday at 03:58:10 PM »
I love the version with the dormer. Would it be possible to do something like this with trusses?
I saw someone on in this group that used parallel chord trusses for a nice cathedral ceiling.
We were wanting a dormer only on the back side. Thinking about doing a skylight on the other side for light/airflow.
Could I use the stair opening to "hide" my support beams? Most of the loft space will be a bedroom.In front of that I'd like to incorporate an open area that looks down into the living room.That area will be where my stairs come to.
Wasn't able to open the file you sent on my I Pad. My son promised to get my new computer up and running for me.  d*

Offline Don_P

  • Journeyman
  • *****
  • Posts: 4,084
Re: Help! Want to expand the 20x30 w/loft into a 24x40 w/loft.
« Reply #14 on: Yesterday at 07:21:48 PM »
The closest truss in Medeek's gallery is a scissor truss, when you sit down with the truss techs they will do the actual design. I've seen the truss sheet you speak of in someone's build thread.  So yes quite do-able. Anyway the 5 minute version in scissors;



A couple of neat things about sketchup, I drew the trusses in about 5 minutes with Medeek's plugin. All of these roof changes are part of the same drawing. I put each roof on its own "layer" and can turn on or off whatever layers I want to view as I work.