Subfloor preparation is one of the most important parts of any installation. As the saying goes: “What’s on top of the floor is only as good as what’s beneath it.” This is especially true with products that are prone to telegraphing every minor imperfection of the substrate, such as resilient.

We spoke with two Starnet flooring contractors—Stephen Cloud, owner of M. Frank Higgins & Co., Newington, Conn.; and Ben Lowery, vice president of operations, Cornerstone Commercial Flooring, Baton Rouge, La.—about their approach to subfloor preparation, budgeting for it and how to keep a client informed going in.

As a contractor, you obviously understand the importance of subfloor prep. How do you make sure your clients are on the same page? Do they generally understand the importance of prep?

Cloud: I think most clients are not on the same page at the beginning of a project. Fortunately we are established enough that I know I can talk a client through the issue to make them understand. We do a lot of resilient flooring where it’s much more critical. We also discuss the moisture mitigation process because that tends to be involved in so many projects.

It can be difficult, though. On a very large job you might find yourself fighting the architect on proper floor preparation. They’re focusing on the sales side of the product and not necessarily the actual mechanics of how the product will perform. They want to do a skim coat where we want to do self-leveling. What we do in that case is finish a small section of the installation first, including washing and waxing. Then they can see how it will look firsthand.

Lowery: Floor prep can be a major point of contention with the client if not communicated properly. Effective communication of expectations and actualities throughout all project stages are keys to an informed and satisfied client. Our approach to floor prep communication is “high-touch.” We touch on the subject with our clients at every step of a project.

How do you budget for subfloor prep?

Cloud: We’re finding that more and more of these projects are carrying sufficient budgets for prep right up front. They might do it as an allowance per square foot, or they might write it into the initial specification. When it isn’t budgeted up front, we push the fact we think of ourselves as more than just a flooring contractor—we want to be full service.

The key is to give them all the information up front. The last think you want to do is just lump it in there with no explanation. They’re going to compare numbers and see yours are higher, and your bid will be thrown out right at the beginning. However, if you can show why your numbers are higher, they might go back to the lower bid and say, “Are you going to include this?” They already have a better impression of you and your professionalism.

My wife and I also do a CEU on moisture mitigation and floor preparation. We go out to the architectural community and present this so they’re educated. Then they start to expect floor prep and moisture mitigation—they understand the need for them.

Lowery: During the budgeting and product selection phase we discuss with our clients the potential need for floor patch and moisture mitigation. We discuss contributing factors such as requirements for the type of flooring, substrate material, substrate condition, new construction vs. remodel, and the client’s expectation for the finished product.

We provide our clients with a budget for floor prep based on our industry experience, but qualify that with actual conditions that will likely affect the budget. We also provide unit prices to them for floor patch and moisture mitigation systems. This way they can make an educated decision of the budget amount they want to include in their cost estimate.

During the contract execution phase we attach a letter to the contract on brightly colored paper that again explains the importance of subfloor prep. We discuss some proactive steps they can take to reduce the amount of floor patch that may be needed and to reduce the chance moisture mitigation will be required—factors such as concrete mix designs, vapor barrier installation, concrete finishing techniques and the importance of controlled air. In this letter, we again give them unit pricing for floor patch and moisture mitigation systems, should they be required.

Most commercial and industrial projects will have a pre-construction meeting. During the scheduling portion of these meetings, we ask that the client allow us to look at the condition of existing substrates after demolition or at new substrates after they are installed. At this critical point of construction, we can assess the substrate and need for floor patch. We also stress the importance of getting controlled air in the building as soon as possible to start optimal drying of the substrate.

As soon as controlled air has been established for 72 hours, we take moisture and pH tests of the substrate. We communicate the results to the client. If there is a potential for moisture mitigation, we begin discussing options at this time. The sooner we can start the dialog on a potential moisture mitigation issue, the less surprised the client is—and clients do not like surprises in the form of additional cost.

During the construction phase our crew leader will walk the project site with the client’s site representative. They will discuss the budgeted amount of patch vs. the amount that may be actually needed. They discuss the process of patch verification. (When we use a bag of patch, we keep the empty bag on-site. At the end of each day, we give the empty bags to the client’s representative along with a patch verification sheet. The sheet describes the amount of patch used, the type of patch and where it was used. The client representative signs the sheet which is then attached to a change order, if needed, and submitted to the client on a weekly basis.)

In general, our clients understand the importance of subfloor prep, mostly because of the experience they have had with us. We try to educate and inform them as much as possible. We do this through the touch points already mentioned and by offering continuing education on the subject to architects, designers and contractors.

Are there any common misconceptions about subfloor prep that installers or contractors have? What’s the most important thing about subfloor prep that you think gets overlooked?

Cloud: It really depends on the flooring. With carpet, for instance, you can get away with pretty much anything. It’s much more forgiving. When you get into some of these resilient products, if you just do a quick skim coat and install over that, imperfections will definitely telegraph through the floor.

Moisture is the largest dilemma. We could talk for hours about moisture testing. If I get a high reading using an RH probe, I encourage the owner to hire a testing company. They know what they’re doing. The last thing you want to do is move ahead with the project based on a false reading.

Existing buildings may not have a vapor barrier underneath it. If the slab is under 10 years old, I recommend moisture mitigation regardless of whether there were issues before. Try telling that to the owner or client, however.

Testing and mitigation is critical. It’s very important for our industry and for the individual to know what to expect, where moisture may be cropping up, and how to perform a test to make sure it’s safe to proceed.

Lowery: Here are the two most common client misconceptions about subfloor prep:

The first: “You are just trying to get more money through change orders.” False. We don’t want to see our client spend additional money that may not have been budgeted. This is why we try to educate and inform them on the front end so the budget can be established. If they save the money, great—they’ll likely do business with us again.

The second: “Controlled air is not needed to dry the slab; it’s been sitting in the sun for months.” False. In order for a slab to dry, there must be a catalyst that creates a reason for it to dry. Dropping the ambient relative humidity in a building is that catalyst. Sure, it can dry in the sun some, but not to the level or at the rate it will with controlled air.

The most important thing about subfloor prep that gets overlooked is you need to be thinking about it and planning for it during the design process. In most cases, a proactive approach can greatly reduce the cost and schedule impact.

What are some of your go-to products when prepping the subfloor to receive floor covering? What do you like about these products?

Cloud: We tend to use a lot of Ardex, USG, MAPEI, Silpro—there are a lot of good products out there. What it really comes down to is comfort level. It’s important my men know the product and get a good comfort level with it. Every time you go out on the job you are opening the door to liability. We think about that when choosing products, so we partner with manufacturers that stand behind their products. If something goes wrong, you need someone who will step up to the plate. That’s what reputations are built on.

Lowery: Schonox APF has been a great gypsum-based leveling product for us. As far as we’re concerned it’s the best gypsum repair product on the market. It has an integrated fiber blend that gives it tensile strength. It actually has the ability to flex and bend without breaking—limited ability of course, but it works incredible over subfloors that have some flex to them.

MAPEI’s line of floor patch is our go-to for cementitious floor patch. We like this line because they have great quality products, excellent technical support and excellent distribution. Their line also covers every imaginable floor patch situation that we might encounter. The MAPEI products we most often use are Planiprep SC, Planipatch, and Novoplan Easy.

For moisture mitigation we have two go-to products depending on the circumstances. VersaShield/VersaShield MBX by Halex Corp., and The LiquiDam by Tec. VersaShield is a great [rolled] product that installs quickly for less schedule impact. LiquiDam is an epoxy moisture barrier that, in most instances, requires less surface profiling than other similar products.