Doing everything right the first time around can seem expensive, especially when the change orders roll in during a project’s plan reviews or during the course of construction. It’s not easy to agree to the extra costs since they ultimately impact the ROI. The question is – can some of these issues be put off until after construction and be addressed at a later time?
It’s a mistake to consider deferring proper waterproofing solutions on below-grade building envelope systems. To do it right, they require proper design and execution with proper and complete inspections. Waterproofing consultants look into the consequences of poorly executed waterproofing and the implications of performing remedial waterproofing.
Proper investigation isn’t cheap
The biggest risk for constructing inadequate building envelope systems is water intrusion. Due to conditions such as groundwater hydrostatic pressure and the capillary action of water, the source of the leak can come from far away.
The process to investigate and develop the remedial waterproofing solution by itself isn’t cheap. Along with initial site inspections, forensic investigation can involve procedures such as excavation pits on the outside and destructive testing such as coring the foundation walls to find out the nature of the underground waterproofing failure.
If the waterproofing system happens to have a manufactured membrane with a warranty issued, to keep it valid you will need to follow the procedures of contacting the manufacturer in a timely manner so they can be present during the investigation (or they can sometimes conduct their own).
The damage to the interior may exceed the cost of the remedy
It is important to quickly address any failures of the below-grade waterproofing. If the remedial solution isn’t done in a timely manner, there’s a risk of water damage to the interior systems and the contents stored in the underground levels. The costs of a flooded building can easily match or exceed the budget for the repair work, and that can be compounded if a tenant files a claim.
The remedy may require multiple trips
If you are familiar with how below grade waterproofing is applied, you know there can be membranes on both the positive side and negative side of the foundation’s walls. Underground waterproofing on the positive side (the outside) is next to impossible for visual inspection, repair, and maintenance, especially on buildings with multiple floors below grade.
Injection type repairs from the negative side could be an effective solution and often the remedy of choice if the leaks aren’t major. Remedial crack injections use either a hydrophobic or hydrophilic material to stop a water leak at the location it is applied. The caveat to this solution is the water is likely to be diverted to another failure point in the membrane, which can lead to repeated costly repair visits.
They may necessitate excavation, backfill and more
The worst case is that a remedial solution has to be applied to the positive side of the waterproofing system. Excavation will be needed to access the membrane that is being repaired or replaced. Not only do you need to remove site features such as landscaping, pathways, ramps, irrigation, but they will also need to be placed somewhere and restore once the job is done. There is also the excavation to manage, this entails stocking the backfill, applying the backfill, re-compaction, and testing.
Excavation, compacting, and performing remedial waterproofing solutions require large construction equipment. If you happen to be in a densely populated setting where the building is bordered by sidewalks and streets, this gets even more complicated and expensive with shoring, street, and pathway closures as well as specialized equipment and materials.
They depend on the hydrostatic conditions
Another factor regarding underground waterproofing is that the building site may have existing hydrostatic conditions. For example, in San Diego, some areas of the city have a high water table. Such conditions could greatly increase the excavation costs and extend the schedule of work as the site goes through construction dewatering (again!).
They may require temporary structures to allow the use of the building
In some unlucky cases, remedial work would be in an area that creates accessibility issues. While rarely the case, it may be necessary to close the building to carry out remedial waterproofing, which would add relocation costs for the occupants. More often than not, the building remains occupied as much as possible and it’s necessary to maintain its accessibility. That means installing temporary walkways, ramps, bridges, and stairs, all of which cost money on a daily basis.
They require more building permits
The building or development departments usually require additional building permits for any work done after the course of construction. This often means it will involve having a licensed architect and/or engineer prepare documents of the remedial waterproofing. Permitting is a time-consuming process.
Need help with waterproofing projects and remedial waterproofing solutions?
If you are considering remedial waterproofing solutions, or if you are researching initial waterproofing and its importance, VERTEX has industry-leading experts in this area. Our team is unique for its versatility and lifetimes of combined experience.
This article was originally published by Xpera Group which is now part of The Vertex Companies, LLC.