Home>Discussions>EXTERIORS>Attaching an addition to an out of level house
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GW - Denver
Attaching an addition to an out of level house
GW - Denver

Hello TOH discussion members. Thanks in advance for any advice you can give.

I'm in the process of adding a 14 X 26 foot addition to the back of our house. The new foundation is placed and I just discovered that the existing house is out of level by 1.5 inches over the 26-foot width of the addition. The new foundation is poured level to the low point of the existing foundation.

I do not want to level the existing house (it is on caissons and seems to be stable).

The addition will be totally open to the existing house house so I need to match the existing ceiling and floor.

Does anyone have any advice on how to handle this situation? Should I keep the depth of the addition(the two - 14-foot walls)level and slope the outside 26-foot wall? If I did this I would shim the sill plate and then grout under the sill plates.

How do you handle framing the walls when the deck is out of level? I had been planning to frame the walls on the deck and then lift them up. If I do this the studs will not be plumb; I'm thinking that I could live with this(except for the corners which would need to be plumb to match the intersecting walls).

Thanks again.

Re: Attaching an addition to an out of level house

If you want your addition leveled and everything to fit you need your house leveled first.

Re: Attaching an addition to an out of level house

not true

you can mesh the existing and hte new t tie in and slowly blend to being level

set the rim board where the floor attaches to the existing flush with the existing portions rim joist keeping the two flush on top then have it level out at the edge of the additions foundation.. from there you will have to stick frame your walls so they work out being level. this is done with a laser level and running string lines, the wall plates will be different lenghts so to keep the outside corners plumb. its more time consuming but has to be done. when you get to the roof system you will also have to do some custom fitting.

it may sound confusing but it has to be done. part of the joys of large scale renovations. i specialize in renovations and large additions.. with new construction you can just use precuts, in renos just about every peice of wood is cut custom

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