Structural Engineering

I’ve reviewed the language in the PBS estimate, and would like a few more clarifications and answers to questions.

1. I’ve been trying to duplicate the numbers for panel square footage (wall, roof, floor) and can’t seem to get within 20% of the numbers. Does Premier use actual panel size or a fixed panel size (4 x 8, 4 x 12, 4 x 16, etc.) and charge for bulk materials? Will the PBS estimate change markedly after the shop drawings are completed?
2. There is no mention of electrical chases in the PBS estimate. Are the custom chases in the roof and some wall panels included in the PBS estimate?
3. I see there is a line item for a spray foam gun and cans. Who is the manufacturer of these products? This project is an attempt at a LEED qualified addition, even though LEED-H is not currently viable for remodeling. I know the mastic is a premier product, but how about the spray foam?
4. It was not evident in the plans, but I should have requested the roof panels plumb cut at the eaves. According to the estimate, roof panels at the ridge are square cut with a ridge cap at 5:12 pitch. Does this then require a field modification to get the one side 5:12 pitch roof to match the 4:12 pitch other side?

I look forward to your answers and suggestions.

Today I got the estimate on the home addition. It falls within 10% of what I was expecting. The house is going to weigh 10,036 pounds, requiring one flatbed truck. The total project is around 400 sq. ft, so it will cost $52 or so per square foot. A typical custom addition costs $150 to $400 per square foot, so we are saving a lot.

I wrote a letter back to Premier:

Thank you for the detailed estimate. It is within the project budget. I’ll review the estimate this weekend and set up the initial shop drawing stage of the order next week. I have a few corrections and questions to the estimate and my account:

The purchaser information has the incorrect city
The project information has the wrong city and zip code. I’ll give you a mobile number I will use at the jobsite too.

My additional questions:

1. What forms of payment does Premier accept (VISA, Discover Card, direct money transfer, check, etc.)?
2. may I e-mail over the signed PBS estimate as a PDF? Or would you like it faxed over?
3. After the shop drawing stage, do I then take those to my LA Building and Safety Department to issue a permit?
4. Jumping into the future: on delivery will I be responsible to offload the panels at the jobsite from the flatbed truck (requiring the use of major material handling equipment)?
5. Do I need to provide all dimensional lumber for window and door openings, top plates, and bottom plate? That is fine since I am planning on using a engineered dimensional lumber from iLevel treated with borates.
6. I forgot to ask if you need a schedule of finishes for the project? Basically the walls will be covered in 1/2 inch gypsum panel, exterior clad in a rainscreen cement board, and roof with metal shingles. I can send you a complete list if it is required.

Let me know if you need to resend the PBS estimate with the corrections noted above. I am excited to finally build this SIP project. Thank you.

After many months of looking for products, suppliers, and vendors, my residential project planning is complete. The structure has cathedral ceilings and high windows for light. The drawings may not emphatically state it, but these are the dimensions of Premier panels I would like to use:

5-1/2″ core thickness wall SIP walls
9-1/4″ core thickness roof SIP walls
9-1/4″ core thickness floor SIP walls

I’ve included both a color and black and white drawing set in PDF format. If there are any details that are missing, let me know, and I can make corrections quickly. Aside from the floor plans and elevations, I have two drawings detailing electrical chases in the roof panels, an extra horizontal communications chase in some of the wall panels, and placement of vertical electrical chases for switches and receptacles.

I assume the standard 16 inch receptacle chases and 45 inch switch chases from floor are include where possible, but I also need a chase at 20 inches from floor for ethernet, cable TV, and telephone on certain walls. The drawing with vertical electrical chases attempt to follow a 4 foot spacing, as comes from the factory, with an exception of a switch in the bathroom mounted near a pocket door. I understand that there should be a vertical chase behind door bucks, or do I need to order those as well? If the panelization process moves the locations of the field receptacle vertical chase locations within a couple of inches, I think my electrical will have no problems wiring the walls to the stated interior dimensions, so take those measures with some flexibility.

There are several door and window openings (three skylights in the roof too), with the rough opening given for all measures taken from manufacturer specifications. The roof plan dimensions may not line up to the drawing, as my architect’s software (Nemetschek Vectorworks) handles roofs oddly, but the stated dimensions are accurate in all directions from the roof ridge.

Here is the process as i understand it going forward:

1. Release and review construction documents
2. Receive an estimate on materials from Premier
3. Approve estimate and send in cash amount to cover shop drawing and structural engineering approval
4. Take drawings and engineering stamped documents to issue building permit
5. Hope City of Los Angeles approves SIP project
6. determine premier manufacturing and delivery and final payment

As I look over the drawings, I see the foundation crawl space continuous spread footings are not well defined, as they are much related to the way the SIP floor is oriented. Perhaps the CA licensed structural engineer can assist once the estimate is done to refine some interior spot footings or additional interior continuous spread footings to support the SIP floor panels, since this project already requires a SIP engineering stamp.

I look forward to Premier’s estimate.

I spoke with you briefly at the JLC Live! 2007 show in Anaheim about the advantages of SIP construction. I have a project starting in a few months that I am considering using PBS products. I have a few questions:

1. What construction documentation do you need? Do you need a floorplan, elevations, exterior wall dimensions, roof plan, etc.? my architect uses a CAD package from Nemetschek called Vectorworks Architect, which can output a 2D PDF file.
2. Does PBS offer a termite resistant OSB skin (BluWood, smartGuard, FrameGuard, etc.)

I am also glad the City of Los Angeles has a research report on your building system.