I must admit, as an architect involved heavily in the home building business for the last 20 years I have never come across the concept of “Brownies vs Muffins.” During a Lean Plan Workout for a large regional builder, Jim, from the concrete supply company brought this concept to our attention. Jim is a salty old timer who has experienced dealing with many different methods of pouring concrete. We were reviewing in detail plans that have been built for years and he asked us if we knew the difference between “brownies and muffins.” I thought sure, brownies are deliciously rich nuggets that melt in your mouth straight from the oven. Muffins on the other hand are a scrumptious bakery cousin. It turned out that he was referring to something else completely unrelated to baked goods.
Jim explained that when pouring a post-tensioned waffle slab all excavators are not created equal. There are crews that dig rigid box like trenches and create crisp, exacting grade beams shaped like a brownie; while others are much looser in their approach and end up digging trenches that create a concrete overflow giving them a muffin effect. I thought that must have everything to do with the soils that they are working with. I could not be more wrong. It had everything to do with the setup and precision of the crews. Jim informed us that he could save an average of one thousand dollars a house (depending on the plan) if the right crews were doing the work, or if the other crews were held to higher standards. This made us sit up and take notice as over the life of the plan at this point they may have been able to capture $500,000 in concrete costs alone! Now that’s a lot of dough!
Now I am constantly on the hunt to turn other muffins into brownies. Starting with excavation and ending with flooring and final touches. The key is to listen and explore all possibilities early in the process. It starts with design. The biggest mistake that can be made is to design in a vacuum, create construction drawings, and then leave the rest for the trades to figure out in the field. They will figure it out alright, but without their input in the design stage we have the opportunity to grease up the muffin pan. The next step is to find the best bakers – both excavators and concrete guys who know how to do it right.