Updating / modifying older plans


  #1  
Old 03-30-08, 07:22 PM
M
Member
Thread Starter
Join Date: Aug 2006
Location: Alberta
Posts: 85
Upvotes: 0
Received 0 Upvotes on 0 Posts
Updating / modifying older plans

Hey folks,

We're doing some investigation right now into temporary accomodation while we design/build our "dream house".

Honestly we were going to buy an old mobile home - but after looking at a few... Building something simple seems more reasonable

http://www.ag.ndsu.nodak.edu/abeng/plans/5965.pdf

I've got a few questions about modifications to the design of this a-frame...

a) can the 2x6's and/or 2x10s be replaced with engineered joists instead of the true dimensional lumber? (The wife's out to go green)
b) I don't see an issue given design, but figured I'd confirm - if I was to add 8' to create a more reasonable size main floor bedroom + bath - other than additional pilings / trusses... Would any modifications be required?
c) if I wanted to add dormer style windows for the upper bedroom - how would this framed to accomodate?

Thanks in advance,

Andy
 
  #2  
Old 03-30-08, 09:18 PM
K
Member
Join Date: Aug 2004
Location: Vancouver, Canada
Posts: 1,126
Upvotes: 0
Received 0 Upvotes on 0 Posts
An A-frame is really useless except as a dwelling. So what are you going to do with it after the dream house is built? Re-use of that lumber to another building will be very wasteful (cutoffs), not Green in the least. Nothing Green about an empty building either.

Even if your site isn't isolated, there will be a need to store a lot of equipment and materials dry, preferably heated. So I think a dwelling that serves double duty would be most practical. Why not build now what will later be a useful outbuilding (garage/storage/shop), and temporarily adapt that as a dwelling? As your dream house nears completion you can cannibalize the appliances and fixtures, even the partition wall studs.

Well..

a) Engineered rafters don't like exposure to elements.

b) The A-frame is freely scalable along its length, just as you propose.

c) I don't know that you could add dormers without increasing the rafter dimension, which spoils the careful economy of that design (you will have to redesign it from scratch, and likely use less efficient lumber lengths). Or the added support would impinge on living space, defeating the purpose.
 
  #3  
Old 03-31-08, 06:20 PM
M
Member
Thread Starter
Join Date: Aug 2006
Location: Alberta
Posts: 85
Upvotes: 0
Received 0 Upvotes on 0 Posts
Oh we've definitely thought of future use After the (hopefully) 2yrs we need it - it will become the "mother in law" suite. We're very sure between friends, family and the mother in laws - it will be full at least 50% of the time (if not full time, we're actually talking about a second "guest cabin" to avoid having spare rooms in the main house.

Shop space is just that - 40x60 metal prefab, however that's not an appropriate living space for a longish term project.

Forgot about the exposure problem with engineered , that pretty much answers that question then. I knew I was missing something obvious.

With 4' o/c rafters - and only looking for a little more natural light (ok - I like a natural sunlight alarm clock; also want some cross ventilation), I was thinking just a simple a-frame dormer (matching pitch of the a-frame) coming off each of the rafters to accomodate a ~24x30" window on each side - I was going to say matching the peak but I could probably stay lower.

Brings up a bunch of issues no doubt, pondering how to deal with insulation at the moment realizing there's more to this than I first thought; not that I dont like a challenge

Thanks for the thoughts/suggestions, still open to more!

Andy
 
  #4  
Old 04-02-08, 04:43 PM
E
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 7,826
Upvotes: 0
Received 1 Upvote on 1 Post
Your post just set me back 25 years into my past. _I_built an A-frame!

More fancy than yours, though. I thad decks that went around the house on 3 sides on both floors. The 2nd story full side-length deck/walkway was cantelevered right out of the house, with no vertical or angled supports. You actually walked between the A-frames that came thru the decks (at the front and rear decks) from the peak and bolted to concrete piers like your pic shows. Had 5 sliding glass doors and a fireplace with faux stone exterior chimney with double or triple lined metal flue inside the chased boxed wood frame.

Oddly, also - _I_ modified the blueprinted A-frame to have 3 dormers so the upstairs could also have an upstairs bathroom + dormers in each bedroom upstairs. Oddly, that side of the house was designed with about an 8 foot (like you mentioned) flat roof extension on it (along at least 1/2 of the left side of the house).

So this is how it worked, and how I did it: On the left side of the house where I made the dormers, the a-frames sat on the interior wall top plates. Had to also incorporate a flitch plate beam to carry the weight of a-frames and upstairs weight that would straddle an open area that did not have that interior wall (at the end of the 1st floor living room, as the living room incorporated the 8 foot flat roofed addition into the width of the living room.) The dormers then were able to sit on that flat roof. In between each dormer, the owner I built the house for, hired out a metal crafter who installed copper flashing between the dornmers that went under the shingles a ways, and also covered the exposed flat roof areas. I designed the dormers at the same 22.5/12 roof pitch as the rest of the a-frame. The house wound up looking like ------------a church, in a way. A nice looking church I was proud that I was able to figure out and build. That was fun and challenging project for me at that age.
 
  #5  
Old 04-02-08, 05:52 PM
E
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 7,826
Upvotes: 0
Received 1 Upvote on 1 Post
With the dormers, you have a couple options.

1. To alter the exterior (let's call it along the left side of the building, as I can equate to that based on what I did), you could eliminate the steep slope along part or all of the left side, and instead build a vertical conventional 8 foot tall wall that will rise from the base at where the base of the A-frame is at floor level. This will gain you more 'useable' space downstairs along that left wall, even though you do not gain any more actual square feet on the first floor, but you would, upstairs, if dormers went out over this. Then, up at the top of that 8 foot wall, you'd joist over to the right a number of feet (whatever that would be - an architectural scaling ruler would tell you) to intersect the existing A-frame roof. The dormers would then sit on this flat roof area.

But here is possibly the good part, or possibly a problem. By doing this, you have to rest those left-side A-frames, that would have to be terminated on a 1st floor top-plate. Which means you'd need an interior wall, running the length of the left side (or part of the left side, as it was with my A-frame house) to carry the top plates and the bottoms of the A-frames. In the place I built, that corridor along the left was for the bathroom and laundry (I originally said 8', but maybe it was 5-6'). That is why it was there. Now, if your plans call for simply open space down there on the 1st floor, and you have no such option with your design to incorporate some corridor along the side of the house inside, then this plan will not work. So then it be onto the other possibility,-----

2. To simply leave the downstairs design the way it is, but simply add on say 2 or 3 dormers along the left side.

Depending on how wide you want the dormers, would dictate how many of the A-frames you would have to header off. The place I built had A-frames about 30 inches apart (they were doubled up 2 x 8's overlapped at the top and bolted together, as you have to remember that with wider rafter spacing, means less support lumber to carry the weigth of the roof!, but since it still has to carry the weight of the roof, doubling up the A-frames (rafters) accomplishes this. They were able to allow that 28-30" spacing by using 1 1/2 inch t & g for the exposed vaulted ceiling upstairs. With such width, I believe all I had to do is head off one of the A-frames to create an ~5 foot wide interior-width dormer.

If your A-frames are closer together, you may have to header off 2 or 3 A-frame rafters. The height of the header would be dictated by geometery based on the roof pitch so that your dormer roof pitch matches the roof pitch of the house.
 
  #6  
Old 04-02-08, 06:17 PM
M
Member
Thread Starter
Join Date: Aug 2006
Location: Alberta
Posts: 85
Upvotes: 0
Received 0 Upvotes on 0 Posts
I'm horrible at descriptions... So, thank god for playing around in sketchup


This is what I'm thinking - this is going by plans with the doubled up rafters at 4' o/c. Basically just removing the sheathing, then framing out... Though I think I would need some additional bracing but that's why I'm asking.

Also see some issues with cold zones depending on roofing material, thinking a steel roof may be best in this type of case rather than trying to keep a cold zone, instead following the plans and having the joists fully filled with insulation.
 
  #7  
Old 04-02-08, 06:46 PM
E
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 7,826
Upvotes: 0
Received 1 Upvote on 1 Post
How did you do that? Interesting.

Is that how it would look, exactly? You woud use the sloped wall of the roof to be like the kneewall, below the dormer window?, to keep someone from falling out the glass?, and basically what you drew would be all window?

You could try toying around with making the dormer with some more protrusion, which may place either the peak higher than where you have it (like I said, you'd have to work that out), and/or by having the dormer go down lower, which may be accomplished by building a VERTICAL kneewall below the window portion. Then the window could be in the upper part of the triangle, with exterior siding below it (and finished wall inside), to make the dormer look bigger. And also from the standpoint of the interior, a person could even walk out into the dormer a little farther.
 
  #8  
Old 04-02-08, 07:01 PM
M
Member
Thread Starter
Join Date: Aug 2006
Location: Alberta
Posts: 85
Upvotes: 0
Received 0 Upvotes on 0 Posts
http://www.sketchup.com/
Very handy little free program for handypeople

Model is properly scaled from the plans, using it to play with other modifications... When I "cut" the window - came off at the interior 'roofline' then came down to roughly 30" AFF. the end wall is missing - was having trouble with planes for some reason. Using the as drawn dimensions looks like a ~20x32" window would fit (have to see what would be a 'standard' size window in that ballpark). That was simply working within the "as designed" structure as much as possible.
 

Last edited by MoreBeer; 04-02-08 at 07:23 PM. Reason: whoops - bad measuring... fixed
  #9  
Old 04-03-08, 06:22 AM
E
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 7,826
Upvotes: 0
Received 1 Upvote on 1 Post
Hi again. To get different perspectives on the looks and function of the dormer(s), I would play around more with some sketches, to try to replicate dormers used on Cape Cods, where these have a vertical wall that is below the window in the dormer, that rests on the top plate (I think) of the floor below. In your case this intersect starting point would be where the upstairs floor and roofline meet.They rise, to standard room height where then it is capped off by a roof.

Since Cape Cod roofs are not as steep (more along the lines of about 12 or 15/12? pitch, in that area, this would make the dormer protrude out from the roof farther than if YOU were to try designing a similar style, since your roof is steeper, it would not look like it protrudes out as far, which is good. But with your current design, it looks too small and minimalistic, IMO, sort of like a window porthole - and also does not have the characteristic of a nornmal dormer where you can actually walk out into it, beyond the roofline. Research the design of the standard dormer. You will see what I mean.
 

Last edited by ecman51; 04-03-08 at 06:43 AM.
  #10  
Old 04-03-08, 11:38 AM
M
Member
Thread Starter
Join Date: Aug 2006
Location: Alberta
Posts: 85
Upvotes: 0
Received 0 Upvotes on 0 Posts
Not really out to get a bunch more floorspace - just to get that nice mountain sunrise alarm clock + some added ventilation over just having windows in the end walls. Which likely explains the minimalist design
 
  #11  
Old 04-03-08, 12:26 PM
E
Banned. Rule And/Or Policy Violation
Join Date: May 2007
Location: Wisconsin
Posts: 7,826
Upvotes: 0
Received 1 Upvote on 1 Post
The skyklight effect, eh? Well, it's your house and is up to you. I just offered another suggestion that maybe you'd try to sketch out to see how it looks. If I had more time on my hands, I'd sketch it out myself, as I am kind of curious. But April 15th is fast approaching!

Your design could very well even look the best, - but I'd still want to see and compare. Good luck. Modifying places can be kind of fun.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: