Replies

1. 
   arnemckinley | Apr 13, 2007 02:17pm | #1

    what do you stand to gain by connecting the structures?. i'm getting the feeling you think the structures should be lagged together. this is not neccessary. what are your concerns if you leave them out?

   as i stated last night the first itme you posted, you want the timberframe to move independently. if you lag to the house ,that movement is impeded. this is not good.

   
   

   ---

   Edited 4/13/2007 7:20 am ET by arnemckinley

1. 
   tom21769 | Apr 13, 2007 04:29pm | #2

   O.K., thanks, and I'm sorry I missed your first response.  (I thought for some reason my first post did not get posted).

   You are restating the conclusion I (the homeowner) had already come to, but my contractor disagreed. His recommendation  is that I should remove all the existing insulation to expose the garage wall, add new 2x blocking, and lag the new timber wall to that. He seems to see a risk that a gap will open between the two walls where the new roof joins the existing wall.  Or, that is simply the way he has always built additions in the past.

   I'm thinking that the new timber frame is almost guaranteed to shrink and swell independantly of the existing wall, and there may be a little settling of the new foundation.  So we should allow for that movement, and account for it in the way we install flashing at the ridge line.  Lag bolts will not prevent movement, they will just propagate the effects as cracks in the frame, or worse.

   I asked the same question on a timber framing forum.  The one comment so far is that I should lag the new ridge beam to the existing studs, without adding any new blocking, and without lagging any of the posts.

    

    

1. 
   Framer | Apr 13, 2007 04:55pm | #3

   >> He seems to see a risk that a gap will open between the two walls where the new roof joins the existing wall. Or, that is simply the way he has always built additions in the past. <<You said that he seems to see a risk about the gap. It doesn't sound like he's to sure of himself. Is he also talking about all the Timber Frame additions he's built?What do the plans say about this, is there a detail?Joe Carola

1. 
   tom21769 | Apr 13, 2007 05:59pm | #4

   No clear detail on the interface between existing garage and addition (fasteners, etc.).  Only a Foundation Plan detail showing the slab and frost (perimiter) wall butted up against what they suppose is the existing garage slab foundation.

   The Timber Frame company sees itself as a frame/wall/window package-provider.  Even though they also provide architectural design services, when it came to foundation & wall interface issues, there is a certain amount  of vagueness and "by others" in the drawings. From the beginning they kept asking me if my county required an engineering stamp, the county said no, and I think the result has been some information is unspecified ("Work it out with your local contractor in the field" etc.)

   So I've been asking a lot of questions in forums like this and at my local building department.  But still feeling some heartburn about the answers.

    

    

    

2. 
   frenchy | Apr 13, 2007 07:24pm | #5

   Hello Tom.

        I have a differant take so please do not think I'm stomping on someone else..

    What wood is your timberframe made of? the reason I ask is that has to do with the way wood shrinks and moves..

      If you are building with a pine/fir/ redwood/ spruce etc..  their shrinkage rates are so similar to the wood your house is built with that it doesn't matter about shrinkage..

     If you are building with a hardwood that changes things a bit.

     not much.. because you see wood swells and shrinks width wise not length wise. (not exactly but close enough for discussion purposes)  so if you lag it together the worst that will happen is the lag connection might loosen a bit as the wood shrinks..

    If you would like to see my credentials go  to the advanced serch function here and type in  85891.1

    those are pictures of my timberframe..

   
   

   ---

   Edited 4/13/2007 12:26 pm ET by frenchy

1. 
   tom21769 | Apr 14, 2007 01:34am | #8

   The frame is Eastern White Pine.I'm thinking the right approach is to lag the ridge beam into the studs (no extra blocking added). Slightly oversize the holes and add some large washers to allow for a little movement. Between the foundation anchor straps/plates at the bottom, and the lagged ridge beam at the top, I don't see a need to lag the posts in the middle.The rationale for lagging at all, I think, is to ensure the posts are positioned snug against the garage wall during the assemby process, and get a flush weather seal between stud wall and ridge beam (with 1/4" foam board in between acting like a gasket).Now, I have virtually zero construction experience -- I'm just the homeowner -- so that's why I'm posting here, to do a sanity check on what we're about to do.

1. 
   frenchy | Apr 14, 2007 01:44am | #9

   Tom

     I would lag things together. you won't need oversized holes as I said wood shrinks and swells width wise not length wise (for all pratical purposes) 

     Any joint needs whatever strengthening it can get.

     you might look at my timberframe if you want examples of added strength..

1. 
   tom21769 | Apr 14, 2007 01:55am | #10

   Thanks for your comments, Frenchy, and by the way, that sure is a fine looking house.
   You don't see construction like that too often. It looks like you must have been influenced by European timber framing with the in-fill walls? SIPS are great insulators and strong, but what you've done really has character.

1. 
   frenchy | Apr 14, 2007 03:20am | #12

   thanxs, 

   What I really tried to do was have it both ways.. Americans timberframe inside so they can look at the timbers, Eurpopeans timberframe outside so they can show off the timbers.. I tried to do both..

    Wound up with walls over 17 inches thick and  a roof that is tornado proof.

    But in your case I'm sure a few extra lag bolts won't hurt and it will strengthen the connection..

    Keep in touch!

2. 
   arnemckinley | Apr 14, 2007 02:17am | #11

   i think that is a good compromise.

3. 
   jesse | Apr 13, 2007 09:42pm | #6

   So lag it. If you are tying the roof of the timberframe part to the existing sidewall, of course you need to attach it.

   Actually, the timberframers I work with have switched almost exclusively to large GRK washer head screws instead of lags when the goal is to hold things together (i.e. when shear is not the issue).

   I fail to see what you stand to gain by having two separate structures when you are shooting for a weatherproof attachment.

1. 
   arnemckinley | Apr 14, 2007 12:17am | #7

   so you think the whole structure should be lagged to the garage? i'm not saying it shouldn't be fastened  at the ridge in one place, but everywhere? i think it would be an incredible amount of work with no benefit, and can't imagine it would be specked even if an engineers stamp were required.

4. 
   zak | Apr 14, 2007 05:15am | #13

   From what I can tell by your description, you should put some blocking in and lag the posts/beams to the old wall- timberlock screws or the GRK RSS screws will work fine.

   Posts and beams will be quite stable in the long direction, which is what you should be concerned about.  The new foundation, if sized correctly, shouldn't settle.

   Wouldn't it be better to lag the two together so you don't get a gap if there is any warpage in the posts?  Or is that not a concern, since this is a garage?

   zak

   "When we build, let us think that we build forever.  Let it not be for present delight nor for present use alone." --John Ruskin

   "so it goes"