Mark on the board where the four support beams are located on your cross beam. **You will need to notch out this area so that the board fits over the support beams**.

**How far apart should rafters be on a pergola?**

Spacing the rafters **16 to 20 inches** apart is common. The most important rule in spacing is to keep the distance consistent between all the rafters. Install the front and rear rafters first, fastening them to the face of the support posts above the girder.

**How far apart should purlins be spaced on a pergola?**

Purlins are spaced **about 3”** apart. Will the unit be attached or freestanding? Attached would allow the pergola to attach to a home or building.

**How far can 2×6 pergola rafters span?**

A 2×6 spaced 16 inches apart can span a maximum distance of **13 feet 5 inches** when used as a rafter, 10 feet 9 inches when used as a joist, and 6 feet 11 inches when used as a deck beam to support joists with a 6-foot span.

Related Question Answers:

## How do you cut notches in rafters?

How To Cut Birds Mouth Notch

## How much can you notch a 6×6 post?

I need to meet 2015 IRC code. Code states that the 2×10 (x2) needs to fully bear on the notched 6×6 post. Also, the thru bolt must go thru a minimum of 2.5 inches of the non notched part of post.

## How do you attach pergola rafters?

How to Build a Pergola – Rafters and Purlins

## How do I stop my pergola from swaying?

2 Answers

- You might consider adding a 2nd screw at each end of each diagonal brace.
- I would put the 2nd screw at a different angle than the original (i.e. if the original lower screw is horizontal, add a 2nd screw at a 45° angle up).
- This may help provide some additional stiffness.

## Can you span 12 feet with a 2×6?

**The maximum distance a 2×6 can span, according to the 2018 IRC, for a floor joist, is 12′-6”**, ceiling joist 20′-8”, rafter 18′-0”, deck board 24”, deck joist 9′-11”, deck beam 8′-3”, and 6′-1” as for header. Always check the codes for determining factors or consult a Structural Engineer.

## What is the best height for a pergola?

The minimum height of a pergola should be no lower than 7’6” to provide enough head room, though most projects call for a range of **8-10′** in height. A lower ceiling feels right-sized for intimate gatherings, while a larger roof is more in scale with a larger structure.

## What size rafters do I need for a 10 foot span?

As per general rules and guideline, for 10 -12 foot span, generally you need **2″×6″** size of rafter, for 15 -16 foot span, you need 2″×8″ rafter, for 18 – 20 foot span, you need 2″×10″ rafter & for 24 foot span, you need 2″×6″ size of rafter placed at 16″ apart from centre.

## How far can a 2×8 rafter span without support?

How far can a 2×8 rafter span without support. Maximum allowable span for a 2×8 rafter:- the maximum allowable span for 2×8 rafter is **21 feet 7 inches when spaced 12 inches apart from centre, 19 feet 6 inches at 16″ OC & 18 feet 6 inches at 24″ OC** with best quality No.

## How far can a 2×8 span without support pergola?

In general, a 2×8 will span 1.5 x 8, so **12-feet**. Based on all factors though, a 2×8 joist span is 7′-1” to 16′-6”, and a rafter 6′-7” and 23′-9”. In this guide, we’ll explain what span means in terms of construction, factors that impact the span, and how much weight a 2×8 can support.

## Do you need a birdsmouth on a rafter?

Whether you’re dealing with studs or an entire wall plate, **using a birdsmouth cut for every rafter is a much more stable way of assembling a roof**. Rather than balancing the rafters at angles on the very edge of the wall plate, you can hook each rafter onto the wall plate, thanks to those triangular birdsmouth notches.

## What is the maximum depth of a birdsmouth cut?

The cut is a ‘birdsmouth’ cut. Rafters may be birdsmouthed to a depth not exceeding **one third of the rafter depth**.

## How do you calculate birdsmouth on a rafter?

Measure or calculate the height of the roof from the top of the wall to the top of the ridge plate and multiply that number by itself. Measure the distance from the outside of one wall to the outside of the other wall, subtract the width of the ridge plate, divide by two and multiply that number by itself.

## Does notching a beam weaken it?

**Improperly sized or placed holes and notches weaken the joist**, make it bouncy and saggy, and provide an easy place for it to crack and fail.

## What is the maximum allowed distance of a notch in a joist from a bearer or wall?

The maximum allowable depth of notches is **one fifth of the joist or rafter depth or 32 mm, whichever is less**. Holes may only be located within a length measured from the face of a support that is no more than three times the depth of the joist or rafter.

## How do you cut a notch in a 6×6 post?

2 Easy Ways To Notch A Post

## Do you need brackets for pergola?

Metal brackets are a popular and excellent material to use when building a pergola. The brackets are graded for outdoor use, and they hold the lumber in place securely and safely. However, because **brackets are required for use on each end of each board**, they do not provide a clean, modern aesthetic.

## What are purlins on a pergola?

Purlins are **the small in size but generally long in length timber lengths that run parallel to the ridge, across the rafters of a pergola and provide fixing points for roofing sheets to be laid**.

## How do you straighten a pergola rafter?

You could **put a row of noggins through the centre using the measurements you have at the ends of your rafters**. This should straighten them enough to look ok. Make sure you put temp brace to hold the outside rafters straight while you nog and leave them on until your cross bracing on the roof is done.

## How long should pergola knee braces be?

I’d make the vertical and horizontal legs of the triangle 1/3 of the post height, unless that causes serious headroom interference, then reduce a bit to **no less than 1/4 of post height**. Much less than that and you won’t see much benefit.

## How do you brace a leaning pergola?

Dig out the dirt along the vertical sides of the pergola. **Add brackets to the vertical sides and add two-by-fours to add support to the structure**. Make sure the support beam is level and secured before covering it. Add a horizontal barrier to the top and make sure that all the parts of the pergola are secure.

## How much weight can a pergola support?

The amount of weight a pergola can hold will vary depending on the quality of the wood and frame design, but it’s typically safe to say that a pergola can handle **at least 300lbs**. Of course, you will need strong chains and attachments that will support that weight as well.

## What size beam do I need for a 14 foot span?

Thus, for a 14 foot span, you will need atleast **3-2×12 or 6×12** size of wood beam. For a 14-foot spans, the wood beam has to be at least 12 inches in depth and 6″ in width (3-2×12) used for residential building, wood frame structure or projects.

## How far can a 2×12 span for a pergola?

How far can you span a 2×12 for a pergola:- as per thumb rule and general guidelines, for a pergola, 2″×12″ size timber you can span it **upto 20 feet** in length. Although it depends on the species and grade of wood.

## How big of a beam do I need to span 16 feet?

For a 16 foot span, you will need atleast **3-2×14 or 6×14** size of wood beam. Thus, a 3 nailed 2×14 or 3-2×14 or 6×14 wood beam can allow to span 16 feet. For a 16-foot spans, the wood beam has to be at least 14 inches in depth and 6″ in width (3-2×14) used for residential building, wood frame structure or projects.