An outside corner has its corner tip pointing away from the protected surface where you are standing, while an inside corner points towards that same surface. When measuring the railing, you must therefore first identify each corner type from the correct side and then measure each railing section and angle according to the measurement method that applies to the railing solution.
It's easy to mix up the corners if you change your perspective during the measurement. Therefore, always start from the side of the railing where you will be standing once it is installed, and measure each corner separately.
In this guide, we'll show you how to identify inside and outside corners, check the angle, and take the correct measurements before ordering the railing.
What is the difference between an inside corner and an outside corner?
The distinction is determined based on the protected side where you will be standing: if the corner tip points away from you, it is an outer corner, and if it points towards you, it is an inner corner. When measuring a railing, each corner must therefore be assessed from the same perspective.
| Here's how to recognise the corner | Outside corner | Inner corner |
|---|---|---|
| The corner tip | Points away from the protected area where you are standing. | Points towards the protected area where you are standing. |
| The railing line | Curves around an outward-projecting section of the deck or floor surface. | Curves around a recess, staircase, or similar section. |
| Typical example | An outer corner of a deck or terrace. | A recess in the deck or a railing around a stairwell. |
| What you need to provide | Whether the corner is an outer corner and what angle it forms. | That the corner is an interior corner and what its angle is. |
So don't change your perspective as you walk around taking measurements. Start from the protected floor area at each corner and check the corner type before moving on to the angle and side measurements.
How do you determine whether a corner is an inside corner or an outside corner?
Stand on the sheltered side of the railing and maintain the same perspective while assessing the corner. If the tip of the corner points away from the floor, it is an outside corner. If it points towards the floor, it is an inside corner.
On-site inspection
Check the corner from the same side every time
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Start on the protected side
Stand where you will be standing once the railing is installed. That is the side from which the corner should be assessed.
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Follow the direction of the corner tip
If the tip points away from the surface where you're standing, you have an outside corner. If, instead, the rail line runs towards the floor surface, you have an inside corner.
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Take a picture from above if the shape is hard to make out
A top-down view makes it easier to see the shape of the floor surface, the direction of the balustrade line, and how the corner actually bends. It is clearer than simply photographing the corner from the side.
The most important thing to remember
Do not switch perspectives between corners. Start from the protected side at each checkpoint; otherwise, the same geometric shape may be perceived as the opposite corner type.
Can a balustrade have both inner and outer corners?
Yes. A single railing can include both inner and outer corners if the floor surface or the railing line changes direction in different ways. Therefore, each corner must be identified and measured separately.
On a deck railing with a recessed section, the railing line can, for example, run toward the house in one place and around the outer edge of the deck in another.
Principle
Follow the rail line and assess each corner individually
When the railing line curves around a protruding section of the floor surface, you will see an outer corner from the protected side. When the railing line instead curves inward around a recess, you will see an inner corner.
This means that the corner types can alternate along the same continuous section of railing. Therefore, be sure to mark the corners on a simple sketch before you start measuring angles and side dimensions.
Does a balustrade corner have to be 90 degrees?
No. Corner type and angle are two different pieces of information. An inside corner or outside corner can be 90 degrees, 135 degrees, or have a different angle depending on the design of the deck, staircase, or floor surface.
If the corner does not form a right angle, the angle must therefore be checked separately. Follow the measurement method specified for the particular railing solution when using the angle for ordering.
- 90 degrees
- A right angle. The corner type still needs to be specified separately because both an inside corner and an outside corner can be 90 degrees.
- 135 degrees
- This may occur, for example, with chamfered corners or surfaces with more than four sides. Here, too, the degree value and the corner type are two different pieces of information.
- Non-standard angle
- When the railing line follows a different shape, the current angle must be measured and specified according to the railing solution's measurement instructions.
- Angled connection
- Where a straight balustrade meets a staircase, the connection must be evaluated in conjunction with the staircase’s slope, in accordance with the instructions for the specific solution.
Measuring tip
If the corner is not clearly 90 degrees, the angle can be checked using a protractor or digital angle finder, for example. Always use the reference points and measurement method specified for the railing solution.
How do you measure inside and outside corners correctly?
Start by identifying each corner from the protected side and then check the angle of the corner and each rail section separately. The length measurements themselves should always be taken from the reference points specified for the railing solution you will be using.
Before using the measurements
Check corners, angles, and sides
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Start from the protected side
Stand where you will be standing once the railing is installed. Examine all corners from the same perspective so that you do not confuse the inner corners with the outer corners.
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Mark each corner separately
Follow the railing line around the entire surface and note which corners are inner corners and which are outer corners. A single railing may include both types.
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Check the angle of the corner
Utgå inte automatiskt från att hörnet är 90 grader. Om vinkeln avviker behöver den mätas enligt den metod som anges för den aktuella räckeslösningen.
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Measure each section of the railing separately
Measure each side individually instead of just specifying the total length around the entire railing. Use the measurement points, any deductions, and reference measurements specified for the balustrade system.
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Match each measurement to the correct side
Feel free to label the sides and corners with, for example, A, B, C, and D on a simple sketch. This will make it clearer which length and which angle correspond to each part of the railing.
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Document the surface from above
An overview or top-down sketch makes it easier to check the shape of the floor area, the railing line, and how the various corners relate to the side dimensions.
Brief summary
Identify the type of corner and the angle before taking length measurements. Then measure each side according to the instructions for the specific balustrade system and link the measurements to a clear sketch or overview diagram.
Are the corners and measurements ready?
Once you have identified the corner types, checked the angles, and gathered the measurements for each railing section, you can proceed to compare a railing solution for the site.
What are some common questions about inside corners, outside corners, and measurements?
Here are brief answers to common questions about how to distinguish between corner type, angle, and railing lengths when gathering measurements for a new railing.
What should I do if I'm not sure whether the corner is an inside corner or an outside corner?
Start from the protected side where you will be standing once the railing is installed. If the corner tip points away from you, it is an outside corner, while a tip pointing towards the protected surface is an inside corner. A sketch or top-down view can make it easier to assess the shape.
Can the same balustrade have several different types of corners?
Yes. A railing can include both inner and outer corners if the floor surface or the railing line changes direction in different ways. Therefore, check each corner separately instead of assuming that all corners are of the same type.
Do I need to specify both the corner type and the angle?
Yes, those are two different pieces of information. The corner type indicates whether the corner is an inside corner or an outside corner from the protected side, while the angle indicates the degree between the rail sections.
What should I do if the corner of the balustrade isn't at a 90-degree angle?
Check the angle according to the measurement method for the specific railing solution. A corner can still be an inside corner or an outside corner even if the angle is, for example, 135 degrees or has a different degree value.
Do I need to measure each side of the balustrade separately?
Yes. Compile separate measurements for each section of railing and, if possible, attach them to a sketch with clear labels. The measurement points themselves and any deductions must follow the instructions for the relevant balustrade system.
Why is a top-down view or sketch useful?
From above, you can see the shape of the floor surface, the direction of the rail line, and how the corners relate to the various side dimensions. This makes it easier to verify that the correct corner type, angle, and length are matched up.
