tall pergola cantilever roof

To begin the process of constructing a new pavilion or other type of outdoor living shelter precise measurements must be taken. The first step is to measure the size of your prospective space to determine how much room you have for your shade shelter and surrounding footprint area.

Typically,  a standard shade shelter has a two-foot roof projection on all sides.  Below are the simple basics of measuring for a pavilion, arbor, gazebo or pergola kit. If you have any questions, reach out to your Design Manager. They are there to ensure your project is a success.

Farrar pavilion with drawing concept


"The instructions that come with it are very self-explanatory. I had a minor problem getting the measurements right. After a quick phone call, I got it straightened out. It was a pleasure working with Western Timber Frame™. - Dewey Farmer - AZ

Plan Out Your Designated Space

Will your pergola be freestanding or attached?

schematic diy pergola kit
attached pergola plan

The type of pergola you have outlined for construction will determine how and what you will need to measure. Other considerations are the outside boundaries and surrounding landscape and what you cannot change. For example, driveways, trees, existing irrigation systems, downspouts, and utilities such air conditioner and heating pump.

How to Measure for a Pergola

Once you know what the scope of your projected plan is, you can begin the moment you have been anticipating, measuring for your pergola. This pictured "check for" and Measure Guide will help launch your vision into reality.

cutting the timber

Measure twice, cut once. This old carpenter's proverb means just what it says, double-check your measurements for accuracy. It is always faster to double-check than to waste time and material.

  1. Measuring Tool Options

Measuring Tape: A measuring tape has a coiled metal strip marked with increments of measurement. A metal tang at the end of the tape allows the operator to anchor the end of the tape to a stationary object and pull the tape to the distant point. There are variations of manual tapes that include cloth tape retracted by a reel.

Laser Measure: A laser measure (also known as an Electronic Tape Measure or Digital Measuring Device) is a handheld, button-activated, electronic device to accurately measure distances. There is no need for someone else to hold the other end of the tape measure and no snapping back from a recoiling of a measuring tape. The operator points and shoots towards an object activating the laser the digitally display the distance. A laser measure is as precise as a manual measuring tape but much faster and more convenient.

Laser Tape Measure: The laser tape measure is two tools in one combining the fast, convenience of laser measurer with the handy convenience of short-span precision in a tape measure.

How to Square a Corner

Measure for 3 4 5

The easiest way to ensure a pergola is square is to use the 3-4-5 Method. To be certain two lines are 90° to each other, measure 3 feet on one line and place a mark. Then measure the other line 4 feet and make a mark. Measure diagonally between the two places you have marked. If it is a perfect 90° for a plumb square it will be exactly 5 feet.

measuring for posts

To layout for your post locations, the sides and angles you would like for your pergola uses the same 3-4-5 Method of measuring. Whatever shape or design you would like your shade shelter to be is easy if you think of it as being on a grid. Though the final drawing may not look square, as long as your measurments are square you will have an aesthetically pleasing layout for your posts.

Bottom of Beam Height

Eight feet is head clearance height for standard shade shelters.

For sloped or step-down areas you will need longer posts and a higher headway.

diy pergola plan

If you are pouring a concrete floor before the pergola installation, deduct the nominal 4″ for posts.
 The posts will need to be longer if they will be below the grade-line.

Other types of pergola structures that need taller than average overhead would be a car stall, boat shelter, farm equipment cover —or when tailoring for a sight-line, etc.

The perfect combination of coziness and wide-open freedom is found in the height of the "bottom-of-the-beam" and roof height. We recommend that you never go under 7 feet height to a bottom beam for headroom.

Measure for a Ledger Board

To anchor a pergola or pavilion to a building requires a timber beam/Ledger Board.

Ledger board for attached pergola

The level or height of the Ledger Board will be the height of the beams that hold the rafters, or bracing for "the ceiling". For the majority of attached pergolas, the Ledger Board will be the length or width of the shade shelter.

For an attached pergola on a conventional lumber framed residence, the height is determined by the location of second-floor level or joists. Brick or concrete buildings can be drilled and bolted in.

sloped roof pavilion

As illustrated above, a Ledger Board can be attached to a floor level that is higher or to add a sloped pavilion roof. In this case, the pergola is technically freestanding and attached.

Measure for Obstructions

measure projection under eaves

Every building is uniquely designed and often residential houses will have eaves that project out.

If the Ledger Board will be anchored between eaves, the pergola can be designed to fit. Measure the roof overhang or pop outs.

attached pergola under roof

Pictured above, the ledger board does not go the full width across to allow for the pergola to extend past the eave.

The Roof Size

The standard overhang of a pergola roof is one foot. If the pergola is an attached pergola, the overhang will only be on the sides not attached to the Ledger Board. If the pergola is unattached and freestanding next to the primary building then there are several roof options. The placement of the posts also come into play. If the posts are set next to the building the roof needs at least 2 inches of space between the pergola and wall. A Cantilevered Roof is an ideal way to extend your shade shelter while keeping your foorprint area (post-to-post) in a smaller area.

Pergola Roof Height

Now, for the height of a standard pergola roof. If a pergola has an eight-foot head clearance, the beams will bring the height up to nine feet, then the rafters will total about 10 feet high. When placed close to a building the stature of the pergola will either be the level of a joist, second-floor level or taller when sheltering an entryway.

Here are 4 examples of higher bottom beams and taller roofs than featured on standard pergolas.

Double Roof

Oriental Asian pergola design

Tiered Pergolas


Pergola Deck

Deck pergola

Arched Roof

Full arched pergola plan
Shop pavilion

Western Timber Frame™ ShadeScape® DIY Pergola Kits are not "cookie cutter" pre-made kits that your living space has to conform to. If an area requires a 25'4" x 30'10" roof, that is what your kit will be, to your measured specs. Each DIY ShadeScape® DIY Kit is pre-cut and pre-tested in the shop for a stress-free fit to your unique area and vision of outdoor living.

If you have questions, call a Design Manager. Your Design Manager will make sure your preferred outdoor living needs are met. He will spearhead your project, so that it is aesthetically pleasing and structurally sound. While insuring that the design is within your budget and time constraints.

radius pergola kit

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