Here are some recommendations from product manufacturers to assure the skylights and daylighting options you install are leak-free and remain leak-free. There’s also some information about repairing leaks.
Geocel® Product Group
Geocel® provides brushable-grade sealants that are an excellent choice for both installing or addressing leaks around skylights or daylighting. Geocel® 2310® Brushable Repair Coating or Geocel® 2315LRF® Leak Repair Fibered Coating can be applied with a chip brush. Only a thin 1/16″ coating, extending 4″ to 6″ around the perimeter of the skylight, can seal many spots where water can enter. A second thin coat is recommended to ensure proper sealing.
Dynamic Fastener sells a product called Drop-Stop®, which is a family of synthetic rubber coatings used for metal roofs and problem areas such as gutters and expansion joints. Drop-Stop® Clear is a brush-grade mastic with unique physical properties for use with skylight panel restoration. Before applying, the area must be free from dirt, moisture, and all foreign material. One could use a brush and water (repeating if necessary) until the repair area is properly clean. Remember to let the area dry before applying Drop-Stop Clear. Apply product in a temperature range of 40°F to 120°F.
Keep in mind, this product is used on the skylight itself. A leak can also occur if the flashing around the skylight might be damaged or corroded and may need to be replaced.
MFM Building Products Corp.
MFM Building Products manufactures a product called Peel & Seal, which is a self-adhering, self-sealing membrane to flash around any exterior roof penetration, including skylights. The membrane is flexible, tough, and durable, and it seals around common roofing fasteners to maintain a waterproof barrier.
Here is a tip: Some sealants will eventually dry and crack, or shrink when fully cured, allowing moisture to enter the roof structure and cause damage. By using a self-adhered membrane like Peel & Seal, the membrane will expand and contract with the skylight and the adhesive system will not crack. Even when the roof system is installed, the membrane will self-seal around fasteners to prevent water leaks. Self-adhered membranes are easy to work with and are oftentimes a less costly method to flash this potential leak area.
Daystar is a manufacturer of complete skylight systems. We prevent leaks in skylights by supplying the roof curb with the skylight. Most manufacturers let the contractor figure out how to install it; we want to own that process. One thing that is very important: the curb we supply with each skylight system is customized to the roof; the contractor doesn’t have to supply a generic item and make it fit. We believe this is one way to reduce leaks.
A successful installation gives peace of mind. The other thing that happens when the customer or the contractor is forced to supply their own curb, is uncertainty when something goes wrong. Who do we get to fix it: the skylight or curb man or the contractor? We like to consolidate that so there is no finger pointing.
It’s very desirable to install the skylight in a way that you never have an issue. We really promote reading the installation manual the day before and then taking the extra time to install it right. It takes a contractor who cares enough to put some thought into how it’s designed to work, with the manufacturer’s planned install method. Then, when you’re ready to start, make sure you have all of the proper supplies, screws, and tools. And, if there’s questions, call us. (Preferably before you install.) We are here to help. We want to avoid installation issues, so you do not have to call six months later saying they all leak. It pays to put a little thought in ahead of time. Don’t be afraid to call, even if you’re on the roof.
When a skylight does leak, the first thing to do is determine if it’s the dome of the skylight or the curb. If it’s coming from the roof, then it’s going to be an installation issue. Somehow you have to figure out where the water is coming in. You need to get down and study the skylight. Possibly you may find a gap in the mastic. Or possibly there are not enough screws. If it’s a gap, the most comfortable for us is to back the screws out and put a new piece of mastic in the gap. Sometimes it’s old enough to have to caulk the gaps after the fact. When it’s still fresh, then we like to fix it using the above method. As a manufacturer, we are here to assist you in a successful, leak-proof installation.
In order to prevent leaks in corrugated polycarbonate light-transmitting panels, it is imperative that installers adhere very strictly to the manufacturer’s installation guidelines.
The most common mistake of an installer is to assume corrugated polycarbonate is installed utilizing the same methods as corrugated metal. While many steps in the process are similar, there are intricacies that need to be followed closely to ensure a leak-free installation. Palram Americas has detailed installation instructions for all of its products, including SUNSKY® corrugated polycarbonate panels.
The use of compatible sealants and correct fasteners is the single most important aspect of the installation. This information is also part of the manufacturer’s installation recommendations.
Quite honestly, once leaking occurs, it is often too late. This is why it is imperative to follow the manufacturer’s installation recommendations. Usually, efforts to resolve leaking result in an unaesthetic appearance.