Estimating the Miscellaneous

February 2009

How do you estimate the backing for miscellaneous items for a project, especially when that backing is not on the plans? We always take off the backing for ADA requirements; however, unless the other backing is shown on the plans, we do not plug in any extra that may occur. It is our position that if the miscellaneous backing for other items is not on the plans or specs, they do not exist in our scope of work. And we always exclude backing not shown on the plans. What do you do?

We typically exclude all backing, unless specifically requested to bid, and price later if scope is provided. We normally ask the GC to layout where required, to limit our liability later on finished walls. If we bid, we call out extent of linear footage in bid.
—Glen Riffe, Area Manager, Denver Drywall Company, Colorado Springs, CO

Exclude it all. Let the general contractor eat it.
—Anonymous

We always exclude backing, either metal or wood, because the plans hardly ever call it out correctly. Some GCs require a backing number that we give in a lineal foot price based on the size and gauge metal required, but not a hard number based off an estimated lineal footage. Most GCs are happy with this because then they get to determine the backing quantity, not the subcontractor. Aloha.
—Todd M. Owner/Estimator, BEK, Inc., Honolulu, HI

You could always use what I call the voluntary alternate. Simply type under your base bid, "Voluntary Alternate.” Look for areas where you would typically install blocking or backing, list them or "qualify” exactly where you may see the need for it, i.e., 2 rows behind cabinets as shown on detail X/X.X. Also explain in the alternate that this was not shown so you took an educated guess. Or, as you’ve stated but in a bold print, under your base bid type, "Exclude all blocking or backing wood or metal.” In my area the local general contractors usually pick that up for their field carpenters, but the out-of-state GCs want as much as possible, for that reason.
—Mike Kellogg, Executive Construction, LLC, Oak Grove, MO

Once we have been awarded the job, the plans are gone over with the project estimator and the job construction manager/supervisor who is in charge or on the job site. After that, if he or she finds any issues not listed on the proposal or on the plans (we always list out items being completed), we will right away bring this to the contractor’s attention for a change order.
—David Marty, Owner/President, First Choice Drywall, Inc., Waunakee, WI

We (a subcontractor) will typically exclude it from our bid unless one of our generals specifically asks us for it. We too follow the ADA requirements, plus we know what backing can be used just from our 28 years of experience. In order to keep apples to apples with our competition, we keep our standard scope of work and most generals are familiar with it.
—D. Parsons, Diversified Interiors, El Paso, Texas

We exclude all backing. —Anonymous

I exclude all backing and blocking from my bids, unless it is for something I am installing. I make this clear on all my bids. I do not install for other trades. Every trade should be made responsible for their own backing/blocking of their work. I will do work time and material to install the backing for others on a project if asked. Always make sure you clearly spell out your inclusions and exclusions on your bid form.
—Anonymous

The general contractor is usually responsible for any backing that needs to be done! Sometimes we put backing in free because if we wait for change orders and other paperwork, it holds the job up. Large change orders are usually done on a time and material basis.
—Dale L. Tucker, Owner, Acoustics, Boise, ID

If the wood backing/bucks are not shown or described on our plans or specs, we always exclude them from our proposals. On the other hand, if the GC or the plans/specs call or request for wood backing and bucks in the areas we’re framing with metal, we’ll gladly submit a bid and perform the work accordingly.
—Alan Castro, President, Advanced Specialty Const. Inc., Fort Walton Beach, FL

When giving a quote or estimate for a project, make note of your deletion of backing in writing from your estimated costs.
—L.A.”Laddy” Dale, Dale Enterprises Inc., Grand Junction, CO

After thoroughly looking through the plans/specs, it should be easy to establish where exactly "backing” should be used. Any instances of grab bars, bathroom acc, or any heavy items that will be hung from the wall more likely than not will require backing. Even though the plans do not call out for "backing,” it should be assumed that these items will require some sort of support.
—Mike McCabe, Estimating, Pinto Construction

If the quantity of backing not shown, is not a big item, I let my super negotiate with the general and do a trade-off on the job. If it is a large quantity, then my project manager will make a decision.
—Anonymous

Backing and/or blocking (wood or strapping) cannot be clearly shown on bid documents but can be properly estimated by review of the specifications and knowing that at all cabinets, wall mounted items, fire-cabinets, handrails, toilet partitions, etc. there has to be some kind of ‘support’ as the drywall system cannot carry the weight of the unsupported items. It is not hard to use common sense and realize that what is internal to the wall system (minus HVAC, electrical, plumbing, etc.) is the responsibility of the wall system contractor. Excluding items at bid time does not make them go away or remove them from the responsible party’s contractual obligations for an all-inclusive bid.
—Anonymous