JimAlsup

Richard, Thanks for the feedback. The two departments (building/planning) occupy the same building and even the same service desk area. They claim they each have/use their own definition. :-(

Rene, It's not about "new service", it's simply about needing to underground the existing service or not.

Rene, It all comes down to the 50% rule. The limit for this project would be 690 sq ft with the definition of "floor area" that does not include the garage. With the garage include we could go up to 890+175, but that puts us over the 750 sq ft rule. So if I can convince the city that the definition they are using is not well defined and they should allow the garage in the calculation, then we could go up to 750 with the addition and not pay for underground utils. Thank you, Jim

Rene, It's a small addition of 650-750 sq ft to an existing home where power lines run across the street (thus the high potential under-grounding cost).

Hello, My city in CA has an underground utility requirement for additions of a certain size. Our desired plan potentially falls over this 50% rule, but we'd like to avoid the est $30K under-grounding cost. The city doc states this (below), but note the use of the term "floor area" which is not well defined. The building department tells me this means livable floor area (garage not counted), but no where in the building department docs or web site is this term defined, nor could they provide me anything in writing. The same term is used by the planning department and they define it as including the garage area. Email to the building department manager has gone unanswered. A definition including the garage would get me 60 more sq. ft. which would meet our goals better. Not that my garage is not 120 sq ft, it just bumps us up to another requirement limit of 750 sq. ft. Building Doc Reference: "9. ELECTRICAL PLAN ➢ Provide size and location of all electrical panel installations. All New Construction, relocated service panels or additions exceeding 50% of floor area, excluding basements and/or additions of 750 square feet or more shall have all utilities installed service lateral. (Underground). *See municipal code section 12.68.020." Planning department reference: "Floor area is the space enclosed by four walls on each floor of a building. It is measured to the outside edge of the exterior walls and includes halls, stairways, service and mechanical equipment rooms, interior courts, garages, carports and enclosed accessory structures. It does not include basements." Searches for this term in the CA building code didn't help me find a definitive definition. I really doubt such a definition would be whatever the city department wants it to be. Thoughts? Thank you, Jim Alsup

Mick, Thanks for the tips. Jim

Thanks for the tip on Xypex, I will do this or something similar. No floor insulation is required for this case, but I certainly will do something (probably the same as I do for the addition floor). I have plans available to me for a number of homes in this 40 home tract home I haven't seen any plans for these homes adding a vapor barrier for the new foundation crawl space. It's not required unless the stem wall is lower than 18". I've also never observed any moisture intrusion in the existing crawl space despite the homes cap cod design (no roof overhang). I don't imagine the costs is high, but I'm not sure about the value. Subterranean termites would be deterred by such a vapor barrier? In this situation I cannot use a rim joist > 7 1/4 inches and any such rim joist would block the airflow. I'm leaning towards reversing the direction of the sleepers to open the space to the crawl space air circulation. In this case I will rest the new foundations 4x8 girder/joists directly on the sill and join perpendicular 2x8 joists to it. This will be no wall over this foundation so floor nailing will not be an issue. I'll try to post an updated foundation pic once I find time to do it. Thank you for you help, Jim

I discussed this with the city today and got a guy who was more responsive. He didn't consult any code docs, but thought I could run sleepers either way and that opening the area to the new crawl space would have advantages. He said no vapor barrier was required under the floor when it was built in '55 and as it's an existing living space, a vapor barrier is not required under the new floor, but suggested it was a good idea. He also suggested batten/net floor insulation at installation time as doing it later would be difficult. So I think I'll go with this approach. Thank you for all your help. -Jim

I happened to talk with someone different at the city today (only had to wait 5 minutes, first and hopefully not the last time that occurs). He said any of the ideas 1- 4 or the slab would work, but the 12 inches under the girders is also fine. I just wouldn't want to be under the house doing anything in such a tight space. I'm thinking of exploring #1 as a starting point and then finish the plan to a level needed to review with potential contractors. Then I'll take it to a structural engineer. Thanks everybody for your help. -Jim

Hello Parkwest, Sorry, meant to say 16 inches off ground level. Jim

Hello Parkwest, If I went with a slab it would need to rise 8 inches off ground level to meet the existing stem wall height. Step downs are not an option. Not sure what the concrete costs would be for that. There will be a lot of plumbing in the slab as the new area includes a kitchen and two bathrooms. I didn't consider this as an option as I am not aware of any home being extended that way in our 40+ track home segment. Many have extended the existing step down family room at slab level but this creates more step down area and we want to ellimate the step down. Do you think the costs would be similar? Thanks, Jim

Hello All, I'm trying to figure out the best way to do the foundation for an addition to our 1955 home. The existing home crawl space is minimal. Perimeter stem wall is 18 inches with 4/6 girders resting on the sill and footings/posts at 4' O.C. . Flooring is 2x6 T&G floor boards resting on the girders. Not sure if that meets modern code. For the new foundation area I was thinking of using 2x8 joists for the floor framing and matching the existing stem wall. I cannot use wider joist without raising the floor as I cannot lower the stem wall height due to code requiring 8" min stem top to group level. The addition needs to span distances beyond the 12' span distance so I need to support them in some way. Girders with posts seems reasonable, but I'm concerned about the crawl space height. 2x8 joists on 18" 16" O.C is tighter than the existing foundation which has 18+5.5 and widely spaced girders dropping it to 18". The new foundation with 4x8 joists at 16" on center and girders would drop the bottom the height to 12" under the beams which seems very tight. I think the code allows for 12", but is it bad practice? Am I wasting my time worrying about this? I have a few ideas on increasing the clearance, but I don't know which would work best and what the cost trade offs are? 1. Move the 4x6 girder to foundation stem wall height and then attach joists with joist hangers rather than resting on top. 2. Build internal foundation footing/stem walls as needed to close 2x8 spans to 12' or less (leave access openings) 3. If legal, copy the existing floor structure. I'm guessing the 4/6 girders and T&G flooring is likely more costly. 4. Extend the addition's stem wall and interior ground level down 6 inches. Slope the soil away from the existing foundation 2" a foot. Excavation and concrete costs go up. Thoughts? Thank you,, Jim

Hello All, I've been to the city building/planning dept a few times for questions. You sign in, wait for your name to come up and then they may or may not be able to answer a question. Time consuming and frustrating. A couple of inspectors gave me their email addresses, but so far they just ignore my questions. I feel like there work time is pretty booked and the only way to get cycles where they will actually help look things up is to travel, sign in, and wait. I think the kind of questions I have this project should be answerable by a local structural engineer. And I will need one for plan checks/signoffs anyhow. Any thoughts on the best way to find one? Thank you, Jim

Hello All, Thank you for your replies. I've answered some questions and asked more based on peoples comments. - Signature Done. - Climate here is great, just a tad, ok more than a tad, smokey these day. Rainfall is 19" a year. Zone 3 according to this: https://www.norbord.com/na/blog/whats-your-building-science-climate-zone/ Regarding Comments from TBIRD1: - #2 I don't know if a VB exists under this 1955 slab. If code required it back then, then I'm sure there is one. There is an existing VB (lining) under the carpet, but that was just something the carpet installer did/suggested. I've never seen any moisture issues, but I will test it at some point, but it sounds like your saying it would be a bad idea. What I really need is a pointer to the code on this kind of retrofit as I couldn't find any myself. - #3 Tables says it's ok to span 12' for 2x8 joists with 16" O.C. Would blocking or bridging at 6' eliminate the bounce? - #4 Yes, I didn't show any ledger on this foundation drawing. The current wall at the edge of this foundation will be gone, so I could change the blocking 2x4.75 over the existing sill into 2 2x4.75 ledgers. This would still give me a way to run the floor structure and have an air opening to the crawl space. - #5 The city told me In our area there is no crawl space VB required unless the interior ground to stem wall top is less than 18". I have attached a pic of my addition foundation outline showing the concrete slab in question. The foundation setup in very incomplete. Thank you, -Jim

Hello All, We're doing a addition/remodel and I need to determine the best way to raise an existing step down family room. Attached off this room will be an addition with crawl space. The attached image shows the design I have using sleepers and joists. This design seals off the sub-floor area from air circulation making it a dead space. Alternatively, I could reverse the direction of the sleepers/joists opening up this small space to air circulation from the attached crawl space. I've look through the foundation sections of the ca 2016 building code but came up empty. Anyone understand if there is a code issue here and if not what the best approach is? Thank you, Jim