Good environmental design means good constructability – and better cost management for developers.

by Heather Martin, VP of Sales for EA

In the environmental contracting and consulting field, there are a number of important details in design and specification, that when properly accounted for can make cost estimates more accurate and construction delays less likely.

In the environmental industry, unknown conditions come with the territory, but the best way to create a seamless project is to manage these unknowns from the beginning of the project. For example, when a developer or owner has hired a General Contractor to coordinate a rehabilitation of an old building, it is likely that it contains lead-based paint (LBP), or asbestos containing material (ACM), or both. An abatement contractor’s estimate will only be as good as the job specification prepared by an environmental engineer.

The specification should outline all locations of the ACM and LBP materials, and their respective quantities, but often they do not account for all locations. In one case at a project in Trenton, an environmental consultant took samples at the existing building at eye-level locations along the wall that appeared to contain LBP. However, once the abatement process began, LBP was discovered at the top level of the roofline as well. This omission cost the owner over a quarter of a million dollars in change orders for the removal. If the initial testing had been more accurate, then at least the owner could have planned better for the actual cost of abatement.

Another example occurred at a site in Queens where the existing roof was sampled and found to be clear of any ACM. However, once abatement began, the contractor found that beneath the wood underlayment to the existing roof, there was an old ACM built up roof. The change order to remove the old roof cost upwards of a quarter million dollars.

When removing contaminated soil or Underground Storage Tanks (USTs), the type of contamination has a profound effect on the disposal cost of impacted soil, particularly between hazardous and non-hazardous wastes. It is difficult to know the exact quantities that will be removed ahead of time, but an engineering estimate should provide a good starting point. In addition, since additional tanks or tonnage may be discovered once digging begins, the GC and owner can have per unit pricing supplied in the bidding phase to at least estimate the costs for additional tons of soil in the case of possible overages.

EAI worked on a site in Queens where the developer wanted to segregate non-hazardous from hazardous soil, in order to reduce the disposal costs. The difficulty arises when you attempt to shore a site, dig fifteen feet, and clearly delineate the two types of material in stockpiles on site prior to hauling and disposal. Proper management of the materials on site, however, can reduce the cost of disposal.

Installation of remedial systems such as a vent system and gas vapor barriers (i.e. liners) can also pose some challenges. Many brownfield sites are redeveloped in conjunction with a sub-slab ventilation system (to alleviate vapors from underneath the slab) and a gas vapor barrier installed above the vent system to prevent hazardous vapors from entering the building through a crack in the slab.

Sequencing is important when installing the vent pipes, particularly if the environmental contractor is not placing the stone. In regards to gas vapor barriers, it is important to account for weather limitations and coordination with other trades. The use of these systems could possibly ease the extent of soil cleanup required and is also a cheap insurance for environmental regulations, which have a tendency to become more stringent with time. Designers can often receive standard specifications and details from manufacturers, which can then be customized as needed to adapt to specific job site conditions.

In the end, developers and owners have to strike a balance between up front investigation and delineation of the environmental scope of work, and the cost associated with the actual cleanup or installation of a remedial system. Competitive bidding is key, as is the reputation and experience of the environmental engineering firm. In short, managing environmental cleanup costs depends on a thorough and accurate preliminary assessment of the site conditions, a realistic evaluation of the costs prior to commencement, and skilled implementation in the field by an experienced contractor.