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experience with sips

won and done williams

i'm looking to design a very inexpensive house using sips. my site has an existing foundation. i'm looking to build up two floors for a total of 1200 sf. my construction budget is only about $100,000. i'm thinking that by using a very simple rectangular plan, i could save quite a lot of money on labor using sips over conventional stick framing. does anyone here have any experience working with sips? is this even reasonable? very much interested in hearing people's experiences with the construction.

 
May 18, 09 8:48 pm
holz.box

100k house used SIPS

here is a flickr of the install.

my only beef w/ sips is they don't significantly reduce cost of construction. from my understanding advanced framing is much cheaper, but i'm probably wrong.

May 18, 09 8:56 pm  · 
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SDR

advanced framing -- can you elaborate ?

May 18, 09 9:13 pm  · 
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holz.box

advanced framing is a system of using less lumber and increasing amount of insulation, saving labor, material and energy costs.

via city of seattle:

Designing and engineering structures for efficient use of lumber and wood materials

Framing one- and two-story walls at 24” on center rather than at 16”
Aligning windows and other openings with framing layout

Use of box headers designed for loading conditions

Eliminating unnecessary studs, such as at corners and T-walls

Eliminating redundant framing such as drywall backer studs and ceiling blocking by using drywall clips.




jafidler, your goal of keeping a compact volume will save money in either method. it will also significantly reduce energy usage. the "swiss box" is an efficient wonder for this very reason...


May 18, 09 10:22 pm  · 
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spaceman spiff

holz,

how about speed of construction? was that significant enough to make a difference in the budget elsewhere?

May 18, 09 11:08 pm  · 
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spaceman spiff

just found the link:

http://www.100khouse.com/

May 18, 09 11:10 pm  · 
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silverlake

Its tough to beat stick framing on cost. Different structural systems and framing variations generally will only save you a marginal amount of money. Finishes are where the greatest variation in cost is...

May 18, 09 11:14 pm  · 
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emaze

keep in mind that while sips are "quick" to install, there may be a long lead time from the supplier, review of shop drawings, and they are really difficult to massage into place if things get messed up.

May 18, 09 11:46 pm  · 
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emaze

and be sure to verify the costs of all the other stuff that may or may not be inculded in the bid. sometimes you need a lot of extra lumber for splines, edge conditons, etc.

May 18, 09 11:49 pm  · 
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spaceman spiff

to save jafidler from having to dig too deep in the link i posted:

http://www.jetsongreen.com/2008/09/prefab-is-not-t.html

a pretty convincing argument against prefab, with a suggestion on how to implement SIPS strategically...

May 19, 09 12:18 am  · 
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won and done williams

thanks, spiff. there were some good points there. like so many successful projects, the key seems to be having a really sharp gc who has worked with and coordinated the system before. i do think that by adding subs (like for sips) you are adding cost over just having your typical builder come in and bang it out.

May 19, 09 8:24 am  · 
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PodZilla

The Burst*008 house at MoMA this past summer was shelled in computer-cut sips panels on the floors, walls and roof.

http://www.treehugger.com/files/2008/07/home-delivery-burst-008.php

Very advanced/expensive, however...

May 19, 09 9:19 am  · 
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sharkswithlasers

As for stick framing and the standard v. advanced diagram -- that looks like a pretty marginal material savings. Maybe multiplied by 100 houses for a builder to do saves something? In any case, the improved R-value seems neglible. The problem is that in both of those conditions, you have a thermal bridge at every single stud. The advanced is hardly better.

Staggering the studs and spraying insulation would get you around that problem and DRAMATICALLY improve R-value. Yes, a few more sticks up front, but over time a much more significant savings in evergy consumption.

May 19, 09 10:24 am  · 
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ether

jafidler, we used them quite a bit for interior mock-up stuff with bill.

also, be sure to give these guys a call when you're ready to get pricing. they're right down the road, have a cnc chainsaw, are reasonably priced and can make them pretty quickly. they are a polystyrene production company but make sips in some extra warehouse space in the back.

May 19, 09 10:24 am  · 
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le bossman

Mr. Fidler

i've done a few. the main place you are going to save money with sips is usually labor, so if your plan is simple enough the difference in cost might be negligible. what we've found is that a stick frame home that is spray-foamed is often preferable to a sips house to the contractor, though i would assume where you are there are at least some contractors that specialize in sips and would prefer or at least be more tolerant of that method.

the best tip i can probably give is that you should stay away from sips panels on the roof and floors as they tend to drive the framers crazy (they are very difficult to set horizontally as they become rather cumbersome, especially after they take the straps off and gravity sets in). in this instance i would always stick frame and then spray in cor-bond or some other rigid foam.

imho the best reason to go with sips is if you have a really tight schedule and you are willing to shell out a little bit more cash to get things done quickly, or at least give your client the impression of things getting done quickly up front (we all know that framing is the fastest phase of construction, then the house "sits there" for another year). they will frame your simple house in sips in a day, stick frame will take a week.

May 19, 09 10:31 am  · 
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le bossman

another thing i would say also is that the up-front lead times for sips for some reason are always a couple months. on projects i've worked on, this was usually way more time than was saved by using sips and usually meant that we would have to change all the drawings back to stick frame anyway, which is also a cost consideration a framer can get out there much sooner, and he doesn't need a skytrak or a crane. personally, i think sips is "neat," but a little overrated.

May 19, 09 10:37 am  · 
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wurdan freo

I have only reserached sips, but remember reading that because they create an impermeable barrier the manufacturer required mechanical ventilation. The question then comes to mind, if it is a perfect summer day and I just want to open the window, do I still have to keep an exhaust fan running? Not sure if the warranty or "no mold" guarantee is somehow linked to cfm changes/hr. Don't remember the details, but threw up a flag for me. Might not be that big a deal for new homes these days. Maybe someone here can speak to that issue.

May 19, 09 10:41 am  · 
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le bossman

you don't need to keep the exhaust fan running. as i understand it, the requirement is due to the fact that the house can't "breath" through the walls and thus air changes don't occur often enough. theoretically, you could suffocate in such a space, but in a practical sense that is nonsense. simply opening and closing the front door brings in a degree of fresh air, and all homes must have exhaust fans in the bathroom anyway. but a whole house fan is not a bad idea, nor are houseplants. it isn't really a mold or mildew thing.

May 19, 09 11:30 am  · 
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le bossman

jfidler why don't you love me anymore?

May 19, 09 11:57 pm  · 
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won and done williams

here's some love, bossman. thanks for all the input. speed of construction is a factor, but it sounds like from others experience, it may be negligible relative to the cost of sips.

wurden's point about air circulation and indoor air quality is a good one. i've often thought it bizarre how tightly we wrap our houses. in my "glass house" which is equally tightly wrapped, the mechanical system is designed so the whole house acts as a return air plenum down to the basement. if you close the opening to the basement, you can feel the air get stagnant, so it's definitely a design consideration.

the two requirements i have for the project are it must be green and above all it must be inexpensive. at this point, i would call the house a challenge more than i would call it a real project. fortunately, the potential client has no interest in dream kitchens and expensive finishes, giving me a lot more freedom to experiment with the building systems albeit on a very tight budget.

May 20, 09 7:55 am  · 
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Antisthenes

none with SIPS
but lots with SABS more efficient and economical in my opinion.

May 20, 09 12:57 pm  · 
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ProjectNorth

We're getting ready to break ground on a SIP home.

Bid was $63,000 delivered to the site.

The square footage is 2435 s.f. (1744 s.f. at 1st floor, 691 s.f. at 2nd floor). This doesn't include the garage, which is a separate structure to be built by stick frame (there's no reason to insulate it, so SIPs make no sense there.)

This includes SIPs for the roof panels (2140 s.f. of roof).

Lead time is shop drawings + 4 weeks to produce & deliver.

We're using an 8" thick panel with an R-value of R-25.

The contractor did a comparison bid to stick framing (5.5" studs) with blown in cellulose insulation, sheathing, gyp, associated labor, etc... and the SIP system was about $15,000 more. But the client is set on using it, and that's fine. It'll be our first experience to do a SIP structure, so that'll be interesting.

Personally, if I were the client, I would have opted to stick frame the house, and used a blown in cellulose insulation, and spend the "savings" on a geothermal heat pump system. We had geo priced out at $20,000 plus $700 to drill three 260-ft. wells. (There was a $2000 tax credit for the geo system as well.) The client opted out of the geo unit because of cost.

If you really wanted, you could wrap the envelope with rigid insulation to help break the thermal bridging of the studs.

I'll reserve my final opinion on SIPs until after the house is built, but my current opinion is that they're not worth it. They may go up in a third of the time, but they also require a greater attention to detail and more planning by the architect and contractor, and those are $'s that are not included in the cost comparisons. Coordinating with other trades is also made more complicated - foundations have to be exact, plumbing & electrical need to be figured out prior to shops, changes during construction are made more difficult.

May 20, 09 4:13 pm  · 
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hillandrock

I'm not sure who what... but I believe SIPS uses OSD(Oriented Strand Board)?

There's rumblings in the planning community to get that particular wood product outlawed.

I have an article around somewhere.. I'd have to scan it... that OSD construction projects run a very high risk of getting slapped as a brownfield due to formaldehyde issues.

May 20, 09 4:22 pm  · 
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SDR

OSB

Geothermal heat pump rocks. Should be standard equipment wherever feasible (lot size ?).

May 20, 09 4:40 pm  · 
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sharkswithlasers

I don't think your information is very current, hillandrock --
HUD did studies on OSB (not OSD) and found that it outgassed at such a low level that it's not a concern.

May 20, 09 4:55 pm  · 
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hillandrock

Yeah but brownfields are also defined by perceived contamination-- there doesn't have to be any actual contamination.

The contamination in question was a company cutting, shaping and working onsite with OSB (SORRY, I kept reading this thread as SIDS as well-- what an awful thing to have an experience with). Instead of cleaning up all the wood chips, they just threw sod over them. Some residents complained and all of the projects had to have their soil scrapped.

It's also just not a gassing issue... it's a groundwater and soil issue.

May 20, 09 5:04 pm  · 
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SDR

Poor (or nonexistent) job-site maintenance and cleanup is surely a separate issue from what materials are in use -- isn't it ? There's a big difference between the effects of materials as incorporated into a structure, and those same materials inserted into the surrounding watershed !

May 20, 09 5:21 pm  · 
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hillandrock

Hey now, I didn't write the rules on brownfield contamination... I was merely suggesting that if you're using the product, to find a credible, clean source of supplies.

And the job-site, structure and clean up is not a separate issue from the use. Many materials in structures will eventually leech out in the environment... sometimes negligible amounts while other times with serious disastrous effects.

Looking at worst case scenario... what happens if the house falls over, goes into disrepair, burns down, rattles apart in an earthquake, gets ripped to shreds and so on. That structure is now in the immediate present environment... and if someone thinks it's contaminated, then by standard it surely is.

There's a marginal difference between "groundwater contamination" and "watershed" as groundwater contamination can be more site specific-- i.e, someone with a shed filled full of hazardous chemicals can lead to seepage in the immediate groundwater and the neighbor next door with a sprinkler pump has been spraying trace amounts of benzene everywhere.

RISK MANAGEMENT!

May 20, 09 5:34 pm  · 
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joshuacarrell

I have used OVE framing techniques in designs to save lumber and increase energy efficiency. As someone mentioned above it will usually come in cheaper than SIPS and get comparable energy performance. Like SIPS, it will increase design time/fees.

j

May 20, 09 5:56 pm  · 
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sharkswithlasers

Sounds like OSD( or B) really has it in for you, hillandrock.

May 20, 09 5:56 pm  · 
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hillandrock

Uh, okay.

May 20, 09 6:36 pm  · 
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snook_dude

I have a project under construction where we are using sip panels on the roof. Everything was fabricated by Mirrus and shipped to the field.
It all went down very quickly due to the experience of the contractor. There were 7 dormers so it was not easy piece to layout for the factory, but they used our drawings and everyone was impressed at how close they hit it.

The walls were conventional 2x6 framed with 2" rigid insulation applied to the exterior and a rain screen beyond the insulation.

oh ya we have geothermal going in as well.

Triple pane low e (2) with argon at windows

double pane low e (2) with argon at french doors

This project is driven by the owners desires, which is kinda fun!

May 20, 09 7:01 pm  · 
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Antisthenes

MONOlythic EPS and GFRC as skin makes allot more sense

do the sq ft calc of just the foam cost then calculate the inside and outside skin area multiply by 1/4" price of getting gfrc sprayed that.

no way that is anywhere close to 60+ k

May 20, 09 7:31 pm  · 
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nonarchitect

For something this small, the difference in price between SIPs and frames will be negligible. Something you should consider is value-engineering the finishes; i.e if there may be innovative ways to use cheap materials for finishes, or leaving some parts "unfinished". You may want to design the simplest house you can think of, and then bid it out. Examine the costs line by line, and value engineer where you need to...

May 25, 09 9:57 pm  · 
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snook_dude

value engineering= more money in the pocket for the contractor and most often a cheap ashe material which will fail in a short period of time.

May 26, 09 7:48 am  · 
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