Replies

1. 
   toddinmaine | Mar 01, 2005 12:46am | #1

   also, would anyone know a good source for framing guidelines(knee wall specific) and building codes, online or not, without having to pay the nearly $85 for the code book? thanks again in advance

   
   

   ---

   Edited 3/1/2005 8:58 am ET by Todd's 1825 Minot, ME home

2. 
   FreeLand | Mar 01, 2005 03:02am | #2

   Try to make some kind of a drawing so that folks can understand exactly what you have in mind.  You need to show current conditions and your proposed changes.

3. 
   nailbanger | Mar 01, 2005 03:26am | #3

   Todd:

   Need to know rafter size & spacing, spans, where in Me is Minot located (what snow zone?), collar ties & where are they located, floor joist size & spacing? All sorts of things, a drawing is pretty key here...

   BILL

4. 
   Piffin | Mar 01, 2005 04:11am | #4

   I'm on Islesboro, Todd. having a brain cramp right now, but shadows in my mind are telling me that Minot's is near here.

   Some kneewalls are structural and some are only there to define space. Since your house was built in an earlier age with different practices than now, normal tables don't apply. The best advice is for you to have an engineer look at it, or a good framer. Transportation can be an issue, so you could take photos and drawings to a PE's office for initial consuult to see if onsite is recommended...

   Or you might get lucky and find your answers here if you can provide the basic information re: how it is structured now.

    

    

   Welcome to the
   Taunton University of Knowledge FHB Campus at Breaktime.
    where ...
   Excellence is its own reward!

5. 
   toddinmaine | Mar 01, 2005 04:45pm | #5

   hey all, thanks for the tips... I will take some pictures and measurements... given the quick reply, I now have alot of faith in this forum and believe I can find my answers among its members.... I should have it up by the end of the day... today, tuesday, March 1st....  not going anywhere... looks as though we're getting snowed in anyways... and for those that asked, minot is just outside of auburn...

6. 
   CapnMac | Mar 01, 2005 07:26pm | #6

   We may need more info on those 'supports' . . .

   Are there any existing dormers?  Any planned?

   Kneewalls are not always for rafter support, often, they are for defining usefull space under the slope.  It's really hard to get any real use of the space under the new sloped to the rafters ceiling once it gets down to 36" above the finish floor.  That could be 36-42" out into your "floor" space.

   If you want a good visual way to "see" some of this, go get a couple, or three, of cheap wood yard sticks from down at the big box or dollar store.  Cut one down to 24" long, and hold it up against the back of the kind of furniture you might have in the new room.  You can take the cut-off and attach it to the top of another yardstick, angling the cut-off to match your rafters.  This, too, can be a very handy way too look at things that will go up against a knee wall.

   Occupational hazard of my occupation not being around (sorry Bubba)
1. 
   toddinmaine | Mar 02, 2005 04:58am | #7

   alright, I have pictures and measurements to go with my previous question... bear with me if I end up give too much info, but I was asked for different things from different people.... but, here goes....

   the original structure again is 25' X 34' (which is an inside measurement, wall to wall) ...the 25' obviously on the gable ends...  the rafters were rough cut 3" x 5", they are layed out between 33" and 36" OC... most closer to 33".... with the roof pitch being  11/12... the first floor ceilings were lowered at one point... with those joists now being rough cut 2" x 8"  layed out between 18" and 24" OC.... they are NOT one long board... they run the 25' span from each side to meet in the middle... these run this way on about 24' of the 34' with the other ones running from those to one of the gable end sides... also rough cut 2" x 8"....

   So, when I bought the house it had old shingles and a sagging roof... the rafter were visibly bowed.... they ripped about 4 layers of roofing off.... left with exposed boards... wasn't pretty.... they then proceeded to use these huge jacks poking thru the roof and raise each individual rafter to the same point along a straight line, then braced it in place. they did both sides, all 68' worth.... once all were relatively straight and braced, they resheathed the whole thing with 4 x 8 plywood... and put architectural shingles...  while the shingling was going on they were "marrying" a 2" x 12" x 8' rafter to the old ones and connecting the sides with a 2" x 8" creating my new second floor ceiling... which they concluded by strapping the whole ceiling....

   so, with this information, I will repeat the original question... I wanted to know if knee walls were "really" needed???  I would like to have as much space as possible... my speculation is that they ARE in fact needed... the roof sagged before, probably would happen again... but, not sure... I don't know if all the new framing would allow me to get away with no knee walls, or if that kind of span (34') should really be supported by a knee wall??? 

   so, given my doubt, if they are needed, is there a minimum distance away from that outside wall that I should place the knee wall? to give it that required support... or is there a required headroom at the bottom of the slope near the top of the knee wall?

   added info... someone asked the "snow zone" of my location... only thing I could come up with referring to that is a "planting snow zone" of most likely "4", but possibly "5"... (map was not exact)   

   ALSO... had problems attaching the pictures I took... really bummed me out... wanted you all to see what I have....  even took a picture of my attempt at building the knee wall, just a short section... I was struggling over the angle and being sure the sheetrock would look right....  but, I've tried uploading for over an hour... will maybe try another time....

   SO, I WILL FINALLY SHUT UP... any help would be greatly appreciated in this matter... sorry if I bored you with all my details... thought more would be better given I couldn't upload the pictures.... thanks again... I'll be looking forward to any of that expertise anyone would care to share, bye for now, Todd

    

    

1. 
   concretedetail | Mar 02, 2005 05:31am | #8

   Coming at you from Vermont, so I'm in a very similar snowload climate. I've seen many houses hereabout like yours.

   Couple questions: has your second story been living space in the past, or are you utilizing this space for the first time? What is the nature of the temp braces you want to remove?

   Your roof repair job sounds like a pretty thorough one. Curious that the crew only sistered up an 8 footer to the 3x5 existing rafter. You will probably need to add rafters between the widespread rough sawn layouts, for wall/ceiling treatments and insulation. The collar ties will help stiffen the roof tremendously. With additional rafters (which should run wall plate to ridge) and corresponding collar ties I should think you'd be in pretty good shape. However, 2x8 floor joists spanning 25' is overspannned, unless there are bearing walls below on the first story. Another question there, I guess.

1. 
   toddinmaine | Mar 02, 2005 05:57am | #9

   thanks watersprite...  the space will be used for the first time.... completely open space 25' x 34'.... would like 3 bedrooms and a bath added up there... my family keeps growing...lol...  I am looking forward to good sized rooms... but, with the knee walls it makes them smaller than I had hoped...   with 2' knee wall space on either side... I would get bedrooms of 10 x 14, 11 x 14 and an 11 x 20... closets in 2 of them.. and a 6 x 10 bathroom.... this is the floor plan I came up with on graph paper... but... would like to turn that 11 x 20 master into 13 x 20 if I could eliminate the knee walls....

   the joists are supported downstairs with a bearing wall running that 24' I spoke of.... you mentioned they are overspanned... does that mean they need to be added to or shored up? god I hope not....

   you asked about the braces... they put those there after jacking the original rafters... came back around and added the 2 x 12's.... at the time I was thinking I wanted/needed the knee walls... BUT, in thinking, and getting space greedy... I guess I was questioning the need for them....  I haven't started anything up there, haven't touched the braces... contractor never took them down... figured he just left them knowing I wanted at the time to put the knee walls.... don't know if that really meant they were required..  I am just researching all the angles before I get going up there... don't want to take them down until I know for sure....

   as far as adding rafters... didn't think I need to do that... thought strapping the slope 16" OC like the ceiling, would be sufficient for the insulation and the sheetrock... you have me questioning that....  as long as there are collar ties above the ceiling, is there really a need to add rafters to the existing ones all the way to the ridge??? 

   so, thanks for the advice... hope you can help with my other questions?

1. 
   concretedetail | Mar 02, 2005 06:24am | #10

   Sounds like the floor joists may be ok for the 24 foot run you reminded me of (sorry) depending where that bearing wall is located (center span?) What about the balance? I think you said the joists in that section ran at right angles, out to the gable wall. I this because of the stairs?

   It would seem to me that if you strapped at 16 oc over 36 oc rafters that you would have sag in your drywall over time.

   Still trying to understand the 2x12x8' that was sistered up to the rafters. It would seem that you would need 10 or 11 feet to run from wallplate to collar at the pitch you quoted.

   The kneewalls (to get back to your original question) will help strengthen the roof but will transfer some of this load to your floor, already stretched. You will lose little usable floor space, but visually , leaving them out, will make the small rooms seem a bit bigger. It seems ambitious to fit all those rooms in that space. You're allowing for wall thicknesses and stair landings?halls?

2. 
   toddinmaine | Mar 02, 2005 06:56am | #11

   jeesh, I like the quick replies... this is a cool site... people informing people... thats a good thing....

   yes, the bearing wall downstairs is about 24' long and comes out 13'... so just over half of the span.....   the reason the others go at a right angle is beyond me... no bearing wall supporting the 10' span... part of that section does set on top of that 13' wall, not just attached to the joists going in the other direction

    its not because of stairs though ... thats a whole separate issue... but, they run up from the center of that bearing wall downstairs, already too steep, up into the slope of the roof on that side..... in wrestling with THAT thought... I am thinking about reconfiguring them once into a set of winder stairs, should be plenty of space..... the stairwell is 4' wide..... most likely winding at top and bottom.... cannot do that until I have heat up there... because I have to tear out the door at the bottom of the flight to accomplish the new stairs... they will come out into the room downstairs beyond that wall.... plenty of room... but anyways.....

   now, why would the drywall sag being attached to the strapping??? that confuses me... glad you told my your opinion, don't get me wrong... just never thought of that one... just more questions... last thing I wanted.. but, important obviously.... I wanna do it right....

   as far as the 2 x 12 x 8... it runs from the top of the vertical wall that is 42" from the floor joist to the bottom of that rafter....  the collar tie is connected to the top of that rafter...

   the room sizes are pretty close estimates... wasn't worrying too much about the 2 x 4 wall thicknesses... but, have the stair landing space, hallway is 3' wide....   think that is standard... other hall on my back addition is that wide...  

   now, what about the knee walls transferring the load to the "already stretched" floor... what consequences could that have?  was afraid to ask but had to... hopefully nothing... but, doubt it....  well, that is enough for tonight... I gotta get to sleep, thanks again... Todd

    

3. 
   nailbanger | Mar 02, 2005 02:18pm | #12

   Todd:

   The weight of the sheetrock is way too much for a 36" span with the strapping. The strapping is not "structural", really only a "nailer", so it will definitely bow down over time.

   Maybe I'm simply being too conservative here but it seems to me like you are trying to push the envelope on a lot of things all at once in order to work within the budget, marginal floor joists in an odd layout, rafter span & spacing (don't forget that to consider the weight of your cieling materials and that any future sagging of the roof will transmit roof load down onto the floor joists through all your new partitions), stair layout, floor space. I think that if I were you I would have someone local look at it and give you a professional analysis of all the factors effecting the project including any local code issues. I have a really bad feeling here. I'm not saying that all of this isn't possible, only that it would be well worth it to have some un-biased eyes take a look at it too.

   BILL

2. 
   SamT | Mar 04, 2005 02:01pm | #17

   Todd,

   First I'ld like to clear up a communications problem.

   You talk about joists or rafters being "married." In this pic, you'll see an example of "Sistered" on the right. I suspect that is what you mean. If they are "Married," let us know, as that creates other issues. For the rest of this post, I will assume thay are "Sistered."

   View ImageTodd Married.gif

   You stated in one of your posts, that the ceiling (soon to be floor) joists are at 18" to 24" OC, and that they were "rough sawn 2x8's," spanning 13'. I don't think that will make it as a floor.

   If you have a Ribbon Framed wall at the junction of the 42" kneeWall (See ??? on the right of "Todd Current.gif" below,) it is fairly easy to lay in the needed floor joists. If your house has been Platform Framed, there are still other issues.

   View ImageTodd Floor to Wall.gif

   It is unlikely that it was Platform Framed, so I am going to ignore those issues also.

   This is the best representation of your house I can do with the information you have given so far. Consider it a "Section View" made by cutting your house in two across the skinny way some where in the 24 foot long area where the joists run the width of

   the house (25'.) The heavy green line are your Sistered (married) 2x's, and the heavy purple is for your new ceiling. What is going on at the green line of question marks? What is the elevation from the top of the Sisters to  the ridge? You say the ceiling (wannabee floor) was moved from the Thick red elevation to the thick blue. What is the floor to ceiling height below the blue elevation? You must have a bearing path at the center wall

   View ImageTodd Current.gif

   from the blue Elevation down to the soil under your house. On the right side of the Pic, you'll see a line marking your proposed new KneeWall. On the left side are it's aproximate dimensions, 16"± by 5' tall.

   If you get all the other issues worked out, such as a strong enough floor and bearing to soil, as well as the Header construction that the 10' ceiling/floor joists on the other end are hung from, You can start to think about your 5' tall KneeWall.

   First remember that the 5' KneeWall is nothing but a people barrior. It can be shelves, closets, or drawers. All can be built-in to maximize storage. You can pick up floor space with the use of dormers that can be one joist bay wide on the inside and any width on the exterior. A built-in 30" deep desk is a sufficient people barrior. You can put a double bay dormer over it and veneer the center roof joist. Make it a "Feature."

    

   Finally, if you are Ribbon Framed, AKA, Balloon Framed, sheathing the bottom of the roof above the  42" KneeWall with 1/2" Ply and replacing the first ceiling strap with a band of equal thickness ply out to the second strap would really go a long way to prevent wall spread. Drywall over it.

   If, in fact you are Platformed Framed, I would build a box beam as shown, above the Ceiling to do the same job.

   Whichever, stagger your joints.

   View ImageTodd Box Beam.gif

   SamT

1. 
   toddinmaine | Mar 04, 2005 05:10pm | #18

   jeesh Sam T. thanks for all the thought & drawings you've put into the reply... a couple quick replies I can do now, the rest of the measurement requests I will have to get back to you later......     

   so, my ignorance has called the 2 x 12 x 8'  "married" to the old rafters, when in fact it is "sistered" as per your drawing...

   the floor joists DO sit on a "bearing path" /bearing wall downstairs which is in the middle of the joist span.... the 2 x 8's come from both sides of the 25' span and meet in the middle sitting on top of that bearing wall.....

   I have been "told" it was balloon framed in the past.... not sure to be positive... and not sure which way the joist are hung/connected to wall.... will find out....

   the green line of question marks is a row of collar ties.... let me run up........phew... there are 2 x 6's.....  they are on every joist the whole 34' front to back.....

   the floor to ceiling (1st floor) below the blue line is just shy of 8'....

   you mentioned soil under the house... this section of the house has a full concrete block foundation.....with those beam sitting on steel posts to the concrete floor of the basement.....

   as far as the knee wall... I had done a small section between 3 rafters to figure what it would look like and show my wife... even sheetrocked at the top of the wall 12" and the bottom of the slope 12".....did this to see how the strapping would work on the slope..... angled a vertical joist at every rafter, and put one in between.. securing the top to a horizontal piece added in...... worked very close to being 16" OC.....  plumbed it all up.... looked pretty good.... and I actually put a nailer behind the bottom of the 2x so the back of my vertical is 24" away from the outside wall.... that created a knee wall "height" of almost 5'...... you measurements had it at 16" away... but, maybe I gave you the wrong roof pitch.... I guess it could have been 10/12 not 11/12 like I said.... 

   SOOOOO, there are a few unanswered questions that I cannot get to now, I cannot bring my little one up, too cold and dangerous for her to be walking around while I measure... hard enough to type while she wants to sit on daddy's lap watching cartoons..... LOL......I WILL however answer the rest tonight.......

   lastly, I think dormers are a ways out of our budget.... hard enough knowing that we still won't finish this year.... will not be done by the spring/summer of 2006.... hopefully.....  and thats crossing our fingers.....

   one final question.... do you use a program to make those drawings??... very nice detail... is it something I could obtain online? or purchase somewhere?... don't need anything extremely detailed..... what did you use? 

   so, thanks again Sam, and everyone for that matter... brought up some very important questions... I do want this to be done right so I don't have to do it again at a future time.... hate to waste money... rather spend it on the kids... have 3 girls, with another child on the way...... we're hoping for a boy this time...

   so, bye for now... Todd

    

    

1. 
   SamT | Mar 04, 2005 08:46pm | #19

   Todd,

   I'm trying to feed you the questions slowly (|:>)

   BTW, all verticle wall framing members are some kind of stud, common, cripple, jack, etc, so your "verticle joist" is a common stud. The "horizontal piece" they're nailed too is a nailer block.

   Roof pitch: if 24" away gives around 5" (60") that is around 18" rise over 24" run or around a 9:12 pitch.

   >>with those beam sitting on steel posts to the concrete floor of the basement.....

   What beams? What steel posts? Are the posts sitting on footings or just the floor?

   "What's a footing," you ask? A footing is a wide and thick concrete base that spreads point (post) or line (wall) loads over the underlying soil.

   Drawings?!?!? Oh, you mean those rough sketches. I use an old shareware version of PaintShopPro, but MS Paint will do as well.

   Balloon framed vs platform. If they lowered the ceiling, it was standard framed before they lowered it and balloon framed now. If they raised the roof it was standard framed before and who knows now.

   Given the ceiling joist dimensions and layout of the firstfloor ceiling, IT IS NOT ACCEPTABLE as an upstairs floor. That means that you will be laying in, not sistering, new taller floor joists for the upstairs.

   In the pic below, on the left is a gable roof. A horizontal member in the upper 1/3 of a roof may be a Collar Tie. A horizontal member in the lower 1/3, may be a wall tie.

   View ImageTODD ROOF.GIF

   You have two roof structures sistered together, a Modified Mansard (middle sketch) with 2x12 rafters and 2x6 roof joists, and a gable roof (RH sketch) with 2x5? (2x8? CRS!) rafters and 2x6 collar ties. Neither roof has wall ties. The wall ties are 42" down the wall, they're not part of your roof. Your Mansard Roof Joists (2x6) are your Gable Roof Collar Ties. Collar ties prevent the tops of rafters from blowing away from the ridge. Wall ties prevent the bottoms of the Rafters from spreading the walls apart.

   With the knowledge of your structure you have given us and the lack of your building knowledge implied by what you have already posted, I suggest that you invest in a framing book, a roofing book, and a foundation book. Or an All-in-One book. My reference is the Carpenters Union textbook, Carpentry, by Leonard Koel, Copyright 1985.

   After you have digested them and analyzed your structure, hire an engineer to complete your plans.

   Good luck, and happy building,

   SamT

    

7. 
   nailbanger | Mar 02, 2005 03:15pm | #13

   Todd:

   Your thread is in two places. Check out the replys in the General Discussions board too.

   BILL

   
   

   ---

   Edited 3/2/2005 7:18 am ET by wrohden

1. 
   toddinmaine | Mar 02, 2005 03:24pm | #14

   yea, the posting in both threads was intentional.. didn't realize administrators didn't like it... think I'll keep it in this construction techniques one...   good info out of both though...  now I have alot of worries... gonna call the original contractor today.. and some others.... I hope all the work wasn't for nothing... spent alot of money... thought it was right, now I have my doubts.... I'll keep looking at the posts, this has been a very enlightening tool in my quest for answers... got great advice... keep them coming....

1. 
   nailbanger | Mar 02, 2005 08:46pm | #15

   Todd:

   Yeah, this is a great forum for questions like yours. Lots of incredibly talented people who are more than willing to share their experience & skills. It's very rare day that I don't pick up something when I come here and read the postings. Good people.

   BILL

1. 
   toddinmaine | Mar 03, 2005 03:19pm | #16

   yea, I appreciate all the advice from everyone... got all worked up with the multitude of "different" opinions.... worried in fact...  then realized as someone said... I don't know who I'm talking to, and started taking the advice for what it is worth.... not that I don't believe or trust peoples advice... but, I know every state is different, every experience is different... and without seeing the ACTUAL space and conditions... it really is just a guess...   so thanks again, and also in advance, given what I said, it will not stop me from using this site... I really do like it... you all brought up some very good questions that I never thought of.....  as well as learning alot from reading what seems like hundreds of the other threads.... information junky I guess... never formally trained in construction... yea, I know, IT'S OBVIOUS..... but I love learning about construction and related things....   I tackle just about anything after I use the info thats out there... I never go blind... always research, research, research..... 

   so, just for more info....

    being an amatuer I guess I used the wrong term... I was figuring 2' from the outside wall as my "2' knee wall"... seems kinda foolish know that I think about it... it is close to 5' when  its 2' from the wall.... the rafters sit on a vertical wall that is about 42" high.... so,  I was thinking 2' of space....LOL.... well anyways... gonna go slap some sense into myself... oh, and BTW, I have the original contractor coming today... another on friday, and others are in the works....calling back.... so, I will have some other "local" professionals looking at it... I'll let ya all know what they said, you can tell me if their right.....  thanks again for the advice