# How to attach an addition to an existing building?



## wingchunbrother (Feb 5, 2011)

I would like to build an addition to an existing building, the existing load bearing wall is at eight feet with a truss roof. I need to go higher that this to get the right pitch for the addition. How do I attach to the load bearing wall(raise it)? Any ideas? I'm planning to run the roof over the existing to make a smooth transition(good drainage).


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## Jackofall1 (Dec 5, 2010)

You would be well served to sketch a drawing up, many times the answers come much easier if you have a visual key to look at, it would also help the forum if you posted that sketch to visualize what it is you are trying to accomplish.

Mark


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## Joe Carola (Apr 14, 2006)

wingchunbrother said:


> I would like to build an addition to an existing building, the existing load bearing wall is at eight feet with a truss roof. I need to go higher that this to get the right pitch for the addition. How do I attach to the load bearing wall(raise it)? Any ideas? I'm planning to run the roof over the existing to make a smooth transition(good drainage).


You frame the kneewall right on top of the existing top plates and nail the studs into the side of the trusses. It also depends how far out your going and the length/span of the rafters. What size opening are you going to have from the existing wall to the new addition?


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## wingchunbrother (Feb 5, 2011)

Kneewall is the term? This will help, thank you.


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## Joe Carola (Apr 14, 2006)

wingchunbrother said:


> Kneewall is the term? This will help, thank you.


Kneewall is the small wall that the rafters can sit on if the trusses cannot handle the weight of the new roof. How far out is the addition?


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## Ron6519 (Mar 28, 2007)

And when the water hits the kneewall at the bottom of the roof slope, how do you plan on keeping the water out of the house?
You might want to look around the neighborhood for ways to do this that incorporates both roof lines. Maybe speak to an architect about proper plans that addresses both ascetics and structural considerations.
Ron


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## wingchunbrother (Feb 5, 2011)

I under stand what your saying, I have some drawings in the works, but to finish them I needed to make sure how I would tie into the existing load bearing wall. I had all ready thought about the kneewall Idea but did not know the term to use. I looked into blueprints but was given a price of $1600.00, this seems very high or a addition of a storage room to a detatched garage. five pilons, Wood floor 16X40, one or two windows, one door, three walls, a few sky lights, a couple of lights and a roof. most of the plans drawn to scale only thing would be makeing sure its all to code. What do you think?


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## Joe Carola (Apr 14, 2006)

wingchunbrother said:


> I under stand what your saying, I have some drawings in the works, but to finish them I needed to make sure how I would tie into the existing load bearing wall. I had all ready thought about the kneewall Idea but did not know the term to use. I looked into blueprints but was given a price of $1600.00, this seems very high or a addition of a storage room to a detatched garage. five pilons, Wood floor 16X40, one or two windows, one door, three walls, a few sky lights, a couple of lights and a roof. most of the plans drawn to scale only thing would be makeing sure its all to code. What do you think?





Ron6519 said:


> And when the water hits the kneewall at the bottom of the roof slope, how do you plan on keeping the water out of the house?



Like I said to Ron in my last post that for no reason at all was deleted, you don't have to worry about that, that's what they make tarps for. The kneewall gets framed and at the end of the day you tarp it. That keeps your house water tight. That's a none issue as far as drawing the plans and presenting them to the town.

Framing it and keeping your house water tight depends on you and how much framing experience you have and how much help you have .

Are you saying that you're going out 16'?

What is the pitch of the existing rafters?

What size rafters on the addition?

If you tell me how far out the addition is and the pitch you want is, I can draw it real quick for you and give you a cross section of what you need.


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## Ron6519 (Mar 28, 2007)

wingchunbrother said:


> I under stand what your saying, I have some drawings in the works, but to finish them I needed to make sure how I would tie into the existing load bearing wall. I had all ready thought about the kneewall Idea but did not know the term to use. I looked into blueprints but was given a price of $1600.00, this seems very high or a addition of a storage room to a detatched garage. five pilons, Wood floor 16X40, one or two windows, one door, three walls, a few sky lights, a couple of lights and a roof. most of the plans drawn to scale only thing would be makeing sure its all to code. What do you think?


I think many localites require a signed plan from an architect or engineer before you get the okay to pick up the tools. Price points will vary from area to area depending on the region and it's permit processes. San Francisco will be different then rural Montana.
Ron


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## AndyGump (Sep 26, 2010)

Joe Carola said:


> Like I said to Ron in my last post that for no reason at all was deleted, you don't have to worry about that, that's what they make tarps for. The kneewall gets framed and at the end of the day you tarp it. That keeps your house water tight. That's a none issue as far as drawing the plans and presenting them to the town.
> 
> Framing it and keeping your house water tight depends on you and how much framing experience you have and how much help you have .
> 
> ...


 Joe, can I send you some plans and have you do them for free too? 

Andy.


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## wingchunbrother (Feb 5, 2011)

I was thinking of going 16' that way I wouldn't need to cut the flore joists the would run from the inside of a 2X12 ledger useing lv210 hangers conecting to the inside of my GLM with Lv210 hangers. The pitch of the roof has not been determind because I was not sure how I was going to tie in to the existing building. one though was to use cleats on the existing roof instead of the knee wall, although I was compleatly sure that was a very good idea. the existing roof is made with trusses not rafters.


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## Joe Carola (Apr 14, 2006)

wingchunbrother said:


> I was thinking of going 16' that way I wouldn't need to cut the flore joists the would run from the inside of a 2X12 ledger useing lv210 hangers conecting to the inside of my GLM with Lv210 hangers. The pitch of the roof has not been determind because I was not sure how I was going to tie in to the existing building. one though was to use cleats on the existing roof instead of the knee wall, although I was compleatly sure that was a very good idea. the existing roof is made with trusses not rafters.


Here's a quick drawing of what you would do. It shows the kneewall if you need it and shows how you tie into the roof at the top. Will this addition be a cathedral ceiling? I drew it as one. If it is and you need the kneewall for sheetrock reasons and breaking the span of the long rafters need be.


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## wingchunbrother (Feb 5, 2011)

The drawing is what I was thinking for the most part, the drawing a friend of mine drew up for me did not have a knee wall just some cleats were you hve the plates. I realy don't care how much pitch the roof has as long as its up to code. the main thing I was thinking was to give the lowest point of the ceiling at least 8'. Not to say I don't need any pitch to my roof but I would be fine with more or less as long as its up to code. I do not have anyway to show you my plans or I would this is mostly just a storage room for lumber so I do need a strong floor and foundation.


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## Joe Carola (Apr 14, 2006)

wingchunbrother said:


> The drawing is what I was thinking for the most part, the drawing a friend of mine drew up for me did not have a knee wall just some cleats were you hve the plates. I realy don't care how much pitch the roof has as long as its up to code. the main thing I was thinking was to give the lowest point of the ceiling at least 8'. Not to say I don't need any pitch to my roof but I would be fine with more or less as long as its up to code. I do not have anyway to show you my plans or I would this is mostly just a storage room for lumber so I do need a strong floor and foundation.


16' addition tying into the existing house where it intersects with the top of the truss with a small pitch will be some long rafters without a kneewall. Well, you have the idea with or without the kneewall. Whatever gets spec'd will do the job. You at least want to put a 4/12 pitch so that you have shingles instead of a flat roof.


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## wingchunbrother (Feb 5, 2011)

I'd like to thank you for all your help, thank you for your time.
Jim


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## pyper (Jul 1, 2009)

Ron6519 said:


> I think many localities require a signed plan from an architect or engineer before you get the okay to pick up the tools.


But there are other localities that don't, and they do their own code review before they approve them. So anyone can draw the plans, and the city will tell you if you need to make any changes. Your tax dollars at work. :thumbsup:

Where I live, you don't even need to submit plans -- you just tell them how much you're going to spend and they give you a permit. It's all about the taxes. They inspect the foundations and maybe the electric. Building a new house I think they look a little more closely, but it's pretty lax for additions and renovations.


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