Would you take a consulting gig where you got paid only if your investigation resulted in at least $2,000 savings per home, hard money? Kind of like the Soup Nazi – either order food his way or no soup for you!
My piece of the job pertained to the structural aspects. My mission:
1) To identify inefficient construction;
2) To estimate its cost;
3) Recommend more efficient, greener methods.
At the end of the day we had to find at least two-thousand, choppable, hard cost dollars or our team’s time and expenses would be donated.
What made this particularly challenging was that we had no previous knowledge of this builder’s homes. What if they were already 100% green and efficient? I like donating to a good cause as much as the next guy, but a private, for-profit corporation?...
Accompanied by the CFO and an owner, we randomly picked one of their 2,000 square foot ramblers in the framing stage. Within five minutes I knew we’d be getting paid. Holy cow, I’ve seen a lot of overbuilding in my day, but this house took the cake. Here are some particulars:
All of this builder’s homes are engineered by the same company, let’s call them Fort Knox Engineering, Inc. (FKE) Before my field visit I spent a day going through a plan set and was impressed with the level of detail FKE provided – four pages of plans plus four more of standard details. Not much risk that the framers would have to guess or call for clarification (if they actually read all that stuff.) However, I was shocked at the amount of wood and metal FKE called for. Particularly considering that these homes are in moderate seismic and wind regions with no snow load.
FKE designed per the 2009 IBC, which is exactly what I would have done. But, if I were the engineer of record, I would have used a different approach for lateral (wind and seismic) design. FKE used only a few interior and exterior shear panels and drug (via drag struts) the rest of the house to them. I prefer using all exterior walls for shear which spreads the load out, minimizing drag struts and holddowns. [Drag struts are straps, blocking, or other horizontally-oriented structural devices that pull and push lateral loads from one part of a building to another.] If you’re sheathing the exterior with OSB anyway, why not have it do some work? Also, I avoid interior shear walls, mostly because getting lateral loads to them from roof and floor diaphragms can be difficult (read expensive.) Occasionally it does make sense to use an interior shear wall, but when I do, I carefully examine the buildability first.
I noted that FKE assumed a wind exposure “C”, which is for open terrain, and which results in relatively high wind loads. This builder’s homes, though, are always in subdivisions which are exposure “B”, a lesser wind load. So right out of the chute, the homes are overbuilt. I might add, they’re not in hurricane or tornado country either, in fact, the general locale has the lowest wind speed, 85 mph, allowed by code.
Straps and Clips Everywhere.
There were hundreds of these in this house. I think FKE must have stock in Simpson Strongtie Company. Now, mind you, I spec framing clips and the occasional strap too, but having been a framer myself, I know that every single one chews up a framer’s time and has material cost.
As an example, all the bird blocks had at least one clip, some two, connecting to top plates. But there were also hurricane ties on all the truss heels. If you run the calcs you’ll find that the hurricane ties alone keep the roof from sliding off the plate. You don’t need to clip the bird blocks too.
There were also straps and blocking around most of the windows. Here is another example of the engineer’s calculation method costing money. Shear walls can be analyzed several ways per code. FKE uses a method which allows less tall shear panels (a good thing) but with that comes the requirement of additional blocking and strapping around the opening. Sometimes this method makes sense but not here. This house has so much available shear wall that to fortify a bunch of window openings is just plain wasteful. I pity the framer cutting all those blocks and nailing all those lineal feet of strapping.
This house has 2x4 studs at 16” OC. Being a rambler (no upper floor loads) in a light wind area, studs could have been spaced at 24” OC. Also, many truss heels have double studs lined up under them which is completely unnecessary. This builder uses double top plates, a good practice I have written about, so lining up studs anywhere is pointless.
I was shocked at how many king studs were doubled. Not trimmers, king studs. The only reason for doubling a king stud is to take big wind load perpendicular to the wall (out-of-plane.) With light wind load and small windows, doubling make no sense.
Trimmers and Support Studs.
There were many instances where headers, beams, and girder trusses were supported by 4, 5, even 6 studs. If you actually calc what’s needed, you’ll find that a single stud works in most cases and a double takes care of the rest.
Doors and windows had cripples at the edges of the opening and at 16” OC. Here is a tremendous waste. Many times, zero cripples are needed. Sometimes only one will suffice. The rest of the time cripples at 24” OC works great.
Every window had a double 2x4 sill. Why? A single would work perfectly well. I wondered if there would be some fancy wide trim or casing needing a lot of wood behind for attachment? No, not the case. It’s just how their framer does it.
Corners and Intersections.
All of these were old-school, 3-studders. There are greener methods.
Foundation Bump Outs.
There were bump outs for architectural features on the exterior walls. Each bump out is an expensive disruption of concrete forming. Generally, if the feature is non-load-bearing it doesn’t need a footing.
Double Interior Walls.
Certain interior walls were intended to have a wide architectural look, achieved using 2, 2x4 back-to-back walls. What about a single 2x6 wall? Almost as wide and a lot less expensive.
All anchor bolts were spaced 4-feet or less. That’s too many bolts, particularly for non-shear walls. One wall had them spaced at 3-inches on center. Yes, you read that correctly, 3-inches. I’ve never seen anything like it, just ridiculous. In a seismic event maybe 1/10 of those bolts would actually see any load, and if there were a failure, the OSB would rip apart from the mud sill way, way before those anchor bolts did anything at all.
It was obvious that window and door headers were not calc’d. There were 4x8s where a 2x6 would work. Interior, non-load-bearing headers which could have been a single, flat 2x4 were 4x4 and 4x6. Just gobs of wood doing nothing, utterly wasted, using up space where insulation could go.
Those were just the big ticket items, there were many more ticky-tacks I won’t mention here.
I think you can see that my time was well spent, identifying well over $2,000 in savings. In fact, before I left I put together a quick spreadsheet tallying up $3,700+ worth of inefficiency – nearly double their goal. And my input was just a piece of our team’s overall mission.
Back in the office I created a Power Point presentation showing photos and explaining each issue. Here is the summary slide:
Correcting overbuilding WILL save considerable money without increasing the risk of structural failure, or violating code.
This was Scott’s 81st Lean Team gig. I don’t know why I was worried going in - we’ve helped builders from New York to San Francisco and in every case unearthed thousands of dollars per home of pure, unadulterated waste. This client was no different.So the story has a happy ending. We got soup, and the builder was ecstatic with their opportunity to save money without sacrificing integrity.