This month the Inspector takes a look at the issue of incorrect material storage:
Incorrect storage of materials is a common issue in the industry and it can have a negative impact on a project’s success from both short and long term perspectives. Materials are often delivered to a project in its early stages and it is therefore essential that they are stored in the correct manner to ensure they perform to their maximum potential, and to achieve trouble-free installation.
Storage on sites can be limited and storage space may come at a premium. However, it is paramount to the project’s success that materials are at least stored correctly. Arguably the most important issue is keeping them dry. Although many products are used for building protection, some cannot fulfill this role until they are actually installed. Simply because a product is considered ‘waterproof’ does not necessarily mean it is suitable to be left exposed to the elements prior to its application without any consequence.
Many materials have natural waterproofing properties but they may still have the ability to absorb or retain moisture prior to being installed. This can then become a problem if the moisture becomes trapped within the system following the product’s application. Trapped moisture within a membrane can lead to a number of issues such as blistering, lap breaches and insufficient bond strengths.
Additionally, some products, such as insulation, will become unusable should they be exposed to moisture (see pic, right). This will reduce the product’s ability to perform as intended from a thermal perspective and the material will retain this moisture, again trapping it within the newly installed waterproofing system. Although insulation, along with a number of other products, may be supplied in shrink-wrap, this is not a reliable protection method when delivered to site. Shrink-wrapping is only used to protect the materials in transit, and the safe and correct storage of materials, once it reaches its destination, lies solely with the contractor.
Wet insulation should be disposed of immediately and should not in any circumstances be used on a project. With the increase of insulation material costs across the industry, it is in everybody’s interest to ensure the product is kept dry and stored correctly. The last thing any contractor wants is to incur additional costs in replacement materials.
Moisture retention in membranes may not be visible to the naked eye, so it’s difficult to tell if the product has retained any moisture during its exposure. The product may well be installed with no sign of compromise. However, defects could become evident months after installation as the trapped moisture expands and contracts through UV exposure and temperature variation. This can lead to blistering and the resulting pressure could affect the integrity of the membrane’s side and head laps. The project could then suffer aesthetically and the contractor could suffer financially having to carry out repairs, something that could have been avoided had the materials been stored correctly at the start.
It is also important that materials are stored at the correct temperature and out of direct sunlight
It is also important that materials are stored at the correct temperature and out of direct sunlight. For example, some bitumen-based products can soften if left exposed to UV and left out in high temperatures, so they should be sheltered from heat and potential solar gain. In contrast, some products, such as cold applied liquids, must be stored above certain temperatures to ensure they can be installed without any compromise to their performance.
Product literature and labelling will always give recommended storage guidance.
Ideally, all products should be safely stored in a container or at least in a dry and cool place. When space is unavailable, the minimum requirement would be to store the materials off the ground and covered with a suitable temporary protection measure such as a tarpaulin or similar.
Just remember, correct storage is the first step to success.