Replies

1. 
   james | Apr 19, 2002 09:51pm | #1

   more details shipsaver, we build additions in the city all the time. would love to help with info.

   is it going up to the property line,

   is it a cantilever ( sp) or on a foundation

   will it create a new roofspace over 200sq feet.

   the more details the more info i can give.

1. 
   user-3172660 | Apr 22, 2002 08:46pm | #2

   James:

   It does go to the property line and is over a foundation.  The foundation itself is canilevered (a Z footing) since I had to hold the foundation off the line to avoid underpinning or replacing my up-hill neighbors foundation.  It is two stories above a full 8ft basement story and does create new roof (and roof deck space) of about 400 sf.

   Thanks.

1. 
   tjcarcht | Apr 22, 2002 08:57pm | #3

   SHIPSAVER - If your construction goes to the property line, then (by definition) any device and/or technique to waterproof the joint between buildings will likely be over the line or partially attached to his/her structure.  Therefore, this is a legal question as well as a design question and a coordinated solution would normally be worked out in close cooperation with your neighbor and with some sort of document memorializing the agreement.  We had a famous (commercial) suit here in town where just such a detail was implemented causing the new building to stray 3/4" over the property line, which resulted in a $1,000,000 + lawsuit.T. Jeffery Clarke

   Quidvis Recte Factum Quamvis Humile Praeclarum

2. 
   Gabe | Apr 22, 2002 10:51pm | #4

   Are you using single faced forms, in other words, forming the inside face only?

   If this is the case, you could drop a sheet of heavy poly against the other building or bank and that would act as your vb.

   Gabe

1. 
   user-3172660 | Apr 24, 2002 06:31am | #5

   Gabe:

   The foundation is already in.  It is the joint between the old and the new siding that I am concerned about.  There is only about two inches between buildings.

   Thanks.

1. 
   Gabe | Apr 24, 2002 02:51pm | #7

   Shipsaver,

   Why do you have a concern about waterproofing?

   Is this area prone to water, poor drainage etc ?

   If you have no water to speak of then fill the cavity with sand and don't worry about it. There has to be a reason to spend money and effort on waterproofing or dampproofing. If you do have a serious water problem, then give me a sketch and dimensions to look at and I'll try to give you a few options.

   Gabe

3. 
   james | Apr 24, 2002 08:35am | #6

   shipsaver, if i understand correctly you currently have a section of your house that runs the property line and you are adding more along the line so you need to tie the new construction to the same plane as the old. we have had success with tilting up the wall with everything in place(sheeting moisture barrier and siding ) and leaving extra house wrap , tar paper etc at the section that will meet the old structure, then you may have to remove an existing stud and run some sort of WP membrane on the interior of the joint along with the extra wrap, paper , or whatever, then replace the removed framing. tuff to explain. try to image waterproofing from the inside of the joint. we also butter up the two edges with a healthy bead of poly sealant.

   on a separate note a roof more than 200sq ft in san francisco needs to have a means of draining to the sewer. 

1. 
   user-3172660 | Apr 25, 2002 07:01am | #8

   James:

   You understand the situation exactly.  Guess I didn't explain it very well in my post.  We are going up two stories over a basement, framing the basement with 2x6 then 2x4 above.  We are planning to tilt the wall into place (haven't decided about balloon framing yet).  I think that I understand your solution.  I'll sleep on it tonight and send along any questions that come up tomorrow. 

   Thanks for your help.