Ever tried to buy replacement blinds or find the perfect sunshade, only to realize you have absolutely no clue what size your skylight actually is? You're not alone! Skylights bring beautiful natural light into our homes, but accurately measuring them is crucial for everything from finding the right accessories and making repairs to ensuring a proper seal and preventing leaks. A wrongly sized shade is useless, and an improperly fitted replacement skylight can cause significant damage to your roof and interior. Getting it right the first time saves time, money, and a whole lot of frustration.
Whether you're planning a DIY project, hiring a contractor, or simply curious about the dimensions of your existing skylight, understanding how to measure it correctly is essential. This guide will walk you through the process step-by-step, ensuring you get accurate measurements for whatever your skylight needs might be. We'll cover everything from identifying different types of skylights to taking precise measurements for ordering replacements or accessories.
What kind of questions will this guide answer?
How do I measure the visible glass area of my skylight?
To measure the visible glass area of your skylight, carefully measure the length and width of the exposed glass pane you can see from inside your home. Multiply these two measurements together (length x width) to calculate the area in square inches or square feet, depending on the units you used. This measurement represents the net daylight opening (NDO) which is a critical factor when considering light output and potential replacement options.
It's important to only measure the *visible* glass. This means ignoring any part of the skylight frame, casing, or any portion of the glass that is hidden underneath the frame. The frame is the part that holds the glass in place and attaches the skylight to the roof. You're interested in the actual area through which light passes.
For oddly shaped skylights (circular, triangular, etc.), you'll need to adjust your approach. For a circular skylight, measure the diameter of the visible glass, divide by two to get the radius, and then use the formula πr² (pi times radius squared) to calculate the area. For other irregular shapes, you might need to approximate by breaking the shape down into smaller, more regular shapes (rectangles and triangles) and then summing their individual areas.
What's the best way to measure a skylight from the inside?
The best way to measure a skylight from the inside is to measure the visible glass area, also known as the "daylight opening," and then measure the interior dimensions of the skylight's frame or curb. These two measurements, when combined, will give you the information needed to identify replacement options or accessories.
Firstly, accurately measuring the daylight opening, which is the exposed glass you can see, is crucial. Use a measuring tape and measure the width and length of the visible glass. If the skylight is a custom shape, take multiple measurements at different points to capture the overall dimensions. Note any curves or angles. Remember to measure the visible glass only, not the frame that surrounds it at this stage. These measurements provide an initial indication of the skylight size, but are not its precise, manufactured dimensions.
Next, measure the interior dimensions of the skylight’s frame or curb. This is the area around the glass that sits flush with the ceiling. Measure the width and length of this frame. If you are planning on replacing the entire skylight, including the frame, these curb measurements are important. Knowing these dimensions is essential when selecting a replacement skylight to ensure a proper fit in the existing opening. Always double-check your measurements to ensure accuracy, as even slight discrepancies can lead to issues during installation.
How do I determine the rough opening size for a skylight replacement?
To determine the rough opening (RO) size for a skylight replacement, carefully measure the *existing* skylight's exterior frame width and length, edge to edge. This gives you the overall dimension of the current unit. Then, consult the manufacturer's specifications for your chosen *replacement* skylight model. The RO size required for the new unit may be slightly different from your old skylight, even if they are supposedly the same "size."
To elaborate, finding the right rough opening dimensions ensures a proper fit for your new skylight, preventing leaks and structural issues. Don't assume that the RO is exactly the same as the old skylight's dimensions. Manufacturers often have slight variations in their products. A skylight that's too small will leave gaps, and one that's too large won't fit at all. Always consult the replacement skylight manufacturer's documentation or website for the precise rough opening dimensions. Look for a "Technical Specifications" or "Installation Guide" section. This information will typically specify the RO needed for each model. If you can't find the information, contact the manufacturer directly. Provide them with the model number of the *replacement* skylight, and they will give you the precise rough opening size. Finally, double-check your measurements. Account for any shimming required during installation. The RO should be square and free of debris, ensuring the skylight sits correctly. Small adjustments might be necessary on-site, but starting with accurate information will save you time and prevent costly mistakes.Should I measure the skylight curb as well as the glass?
Yes, you should absolutely measure both the skylight glass (or acrylic) and the curb (the raised frame upon which the skylight sits). Measuring both accurately is crucial for determining the correct replacement size or when ordering a new skylight, ensuring a proper fit and preventing leaks.
The glass measurement is primarily used to identify the skylight model or size group. However, the curb measurement is equally important because it dictates the rough opening size in your roof. If you're replacing an existing skylight, knowing the curb dimensions ensures that the new unit will seamlessly integrate with the existing opening without requiring modifications to the roof structure. Failing to measure the curb can result in ordering a skylight that is either too large or too small, leading to significant installation headaches and potential water damage.
Specifically, you will want to measure the *exterior* dimensions of the curb. Measure the width and the length of the outside of the curb. If you are replacing the entire skylight unit (glass and curb), you will need to provide BOTH the glass and curb measurements to your supplier. They can then determine the appropriate replacement unit, taking into account both the visible glass area and the necessary dimensions for proper installation and flashing.
What's the proper way to measure a domed skylight?
Measuring a domed skylight accurately involves taking both the outside curb dimensions and the interior daylight opening dimensions. The curb dimensions define the overall footprint needed for replacement, while the daylight opening determines the visible light area. It's essential to specify whether the measurements are interior or exterior and include the dome height if possible.
When measuring the outside curb, measure the length and width from the outside edges of the curb – the raised frame the skylight sits on. Ensure you measure the widest points. This measurement is crucial for ensuring a new skylight unit will properly fit onto the existing roof opening. Note the material of the curb, as this may impact replacement options. If you're replacing the entire unit (skylight and curb), this measurement becomes even more critical. To obtain the daylight opening measurement, measure the visible area of the skylight from the interior of the building. This is the area of the skylight that allows light to pass through. You can typically obtain a fairly accurate daylight opening dimension by measuring between the interior edges of the skylight frame. Take multiple measurements across the length and width, as slight variations can occur. This measurement is useful for determining the size and type of replacement skylight you need to maintain the desired amount of natural light in the room. If the skylight is severely damaged or leaking, consider professional assistance to ensure accurate measurements and a proper installation. Finally, measure the dome height from the top of the curb to the highest point of the dome. This helps ensure adequate clearance and aesthetics, especially when replacing with a similar domed unit.How accurate do my skylight measurements need to be?
Your skylight measurements need to be accurate to within 1/8 of an inch, especially when ordering a replacement or custom-sized skylight. Precision is critical for ensuring a proper fit, preventing leaks, and avoiding costly installation problems. Rounding too liberally can lead to gaps, alignment issues, or even the inability to install the new skylight at all.
The level of accuracy required depends on the purpose of your measurements. If you're simply trying to get a rough estimate for budgeting purposes or exploring skylight options, being within a quarter inch might suffice. However, when it comes time to order the skylight, meticulous measurements are non-negotiable. Small discrepancies can compound during manufacturing and installation, leading to significant issues. Always double-check your measurements, and if possible, have a professional installer verify them before placing an order. Keep in mind that different parts of the skylight may require different levels of precision. For instance, the rough opening in the roof needs to be accurately measured to ensure the skylight's frame will fit snugly. The size of the glazing (the glass or plastic panel) is also important, particularly if you're replacing only the glazing and not the entire skylight unit. Moreover, when measuring for flashing kits, precision is vital to ensure a watertight seal. Using a quality measuring tape and taking your time will contribute to a successful skylight project.What units of measurement should I use for my skylight?
When measuring for a skylight, use inches (") for precision and consistency within the North American building and construction industry. While centimeters (cm) or millimeters (mm) might offer finer granularity, most skylight manufacturers, installers, and related materials are specified using imperial units.
Using inches avoids potential conversion errors and ensures compatibility with standard construction practices. A fraction of an inch can make a significant difference in fitting a skylight correctly, ensuring a weather-tight seal, and avoiding costly rework. Therefore, measure to the nearest 1/8" or even 1/16" if possible, especially when determining the rough opening or the dimensions of the existing skylight you're replacing. Remember to consistently apply the same unit of measurement throughout the entire process, from initial measurements to ordering the skylight and its components. Double-checking your units before submitting any orders will save time, money, and frustration. Verify with your supplier which unit is preferred by them.And that's all there is to it! Hopefully, you now feel confident in measuring your skylight. Thanks for reading, and good luck with your project. We hope you'll come back and visit us again soon for more helpful tips and tricks!