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Constructing a Three Gable Timber Frame Garden or Patio Covering Pavilion

By November 25, 2018 April 12th, 2019 One Comment

Build your own Three Gable Timber Frame Pavilion.  Plans available for download in PDF Format.

See the How to Video.

My good friend Connor and his wife Sara asked me to help them build a pavilion in their back yard. They wanted a timber frame three gable structure so I modeled up a design in Sketchup and drew up some plans.

Build the Timber Frame Style Pavilion

The Sketchup Model

The posts will sit on formed concrete piers. There’s two beams running North to South. And two beams running East to West. Corner braces add rigidity to the frame at the intersection of the beams and posts.

Sketchup model of pavilion

Sketchup model of pavilion

King posts sit mid span on the beams and support the upper ridge beams. Valley rafters run from the peak to the corners and support the jack rafters.

Valley and Jack Rafters

Valley and Jack Rafters

Common rafters finish the gable ends and the West facing roof slope.

Valley and Jack Rafters - Three Gable Pavilion

Valley and Jack Rafters

Strapping is laid over these rafters and over the jack rafters on the Northeast and Southeast corners.

Three Gable Pavilion - Valley and Jack Rafters

Valley and Jack Rafters

The roof is finished with plywood then metal sheet.

Three Gable Pavilion - Metal roof panels over plywood

Metal roof panels over plywood

I have a full set of plans available for download.

Forms for the Footings and Piers

We cut into Connor’s deck and built batter boards to lay out the footings and concrete piers to support the structure. I used string drawn over the ledger boards to locate the center of each post.

Three Gable Timber Frame Pavilion - Layout of post forms done with string and batter boards

Layout of post forms done with string and batter boards

The strings are kept taught with bricks. They can easily be adjusted or pulled out of the way if needed.

Bricks hang from each end of the strings to keep lines tight

Bricks hang from each end of the strings to keep lines tight

The string lines are squared so the posts are 10′ x 10′ on center.

On 10' x 10' centres

On 10′ x 10′ centers

I leveled the tops of all the forms so they would be on the same plane. I used a laser level to help with this.

With all post form tops on the same level I can then cut my posts all the same length

With all post form tops on the same level I can then cut my posts all the same length

The pavilion is made from Douglas Fir rough sawn from a local mill.

The posts sit on adjustable galvanized saddles attached to an anchor bolt embedded in the concrete.

Adjustable galvanized post saddles and anchor bolt

Adjustable galvanized post saddles and anchor bolt

The plywood forms are coated on the inside with vegetable oil then concrete poured in.

Cement mixed in wheelbarrow, shovelled into pier forms, then anchor bolt worked in

Cement mixed in wheelbarrow, shoveled into pier forms, then anchor bolt worked in

They are covered with plastic and left to cure for several days.

Wet cement in pier forms covered with plastic to cure for several days

Wet cement in pier forms covered with plastic to cure for several days

The screws are then removed and the forms stripped.

Saddle attached to finished post pier

Saddle attached to finished post pier

Posts and First Beams

I shot time lapse for most of this build. The posts are cut to length then screwed to the saddles, plumbed, and held in place with temporary braces.

Standing posts on saddles and bracing

Standing posts on saddles and bracing

The four 6×6 beams are laid on sawhorses while I check the spacing of the posts with a tape measure. I also double check that they are plumb before I lay out and cut the first beams.

Checking all post dimensions before laying out and cutting any beams

Checking all post dimensions before laying out and cutting any beams

The North/South set of beams have a 45 degree chamfer on each end and two opposing grooves. The upper groove is 2″ deep and the lower groove that sits on the post top is a half inch deep.

First two beams sit down on post tops

First two beams sit down on post tops

With the posts in their final position, I cut the North/South beams to length with a circular saw.

Next I lay out the upper 2″ groove and Connor makes a series of thin slices into the beam with a circular saw. These are then broken off with a hammer then the groove (or lap) is cleaned up with a chisel.

Three Gable Pavilion - Cutting grooves in first beams.

Cutting grooves in first beams

I lay out and cut the shallower groove on the opposite side of the beam in the same fashion as the first grooves.

These four grooves are then cut into the other beam.

The chamfers in the ends of the beams are cut with a circular saw set at a 45 degree angle. A large square is used as a guide.

The first beam falls into place on the second try.

The first beam falls into place on the second try

The first beam was lifted into place but the groove on my end was too tight, so we brought it back down and trimmed it a bit.

And we tried it again and this time it fit. A few screws will hold the beam in place for now.

Three Gable Pavilion -- The second beam lifted into position.

The second beam lifted into position

The chamfers are cut on the ends of the next beam and it’s lifted into place.

The East/West beams have 2″ deep laps that are open on the West end. On the other end, grooves will fit tightly over the North/South beams.

Pergola - Crossing beams

Crossing beams

Countersunk holes are drilled in so a long lag bolt can secure the four beams to the posts.

Measurements are double checked, then these beams are laid out. They are cut to length and the grooves cut as before.

The East ends are chamfered in the same manner as the other beams.

Sliding the third beam into place - gazebo building

Sliding the third beam into place

The first beam is brought up and laid over the two North/South beams. Then it’s slid over and into place.

My end didn’t fit so we lifted it back out. I grabbed a taller ladder and circular saw and opened the groove up a bit. Then this beam fell in nicely.

This beam fell into place after making a small cut to open the groove up a bit

This beam fell into place after making a small cut to open the groove up a bit

We lifted the last beam and laid it across the frame then slid it over and dropped it into place.

High five!! First four beams in place

High five!! First four beams in place

And that’s the end of a very satisfying day.

Make the Curved Braces

For this structure I designed two similar braces. For the inside corners I have a small curved brace. These are made from 3″ thick stock. Connor’s neighbour, BJ, was kind enough to let us use his shop to make the braces.

Three Gable Pergola - Tracing plywood pattern brace shape onto fir board

Tracing plywood pattern brace shape onto fir board

Beforehand, I made two plywood patterns for the brace designs. Here Connor is tracing the outline of the smaller brace onto stock. And trying to avoid any knots if he can.

Mitre Saw

Miter Saw

He cuts two opposing 45 degree angles on the miter saw.

Hand saw to finish cuts

Hand saw to finish cuts

Finishing each cut with a hand saw where the circular blade didn’t reach.

Cutting the curves of the braces on a bandsaw

Cutting the curves of the braces on a band saw

I took these to the band saw to cut the curves.

Sanding the braces

Sanding the braces

Then over to the sander to smooth the rough spots.

The outside braces are slightly larger. As before, the pattern is traced and the angles cut. There’s a small 90 degree cut in the corner, and that’s done on the miter saw as well.

Cutting the corners of the braces

Cutting the corners of the braces

These too are taken to the bandsaw to cut the curves then on to the sander for finishing.

Sanding the back curve of the larger brace

Sanding the back curve of the larger brace

Stops are clamped to the drill press table and it’s tilted 20 degrees. A forstner bit is used first to countersink the head of the lag bolt that will secure the brace to the posts and beams.

Countersinking on the table saw with a forstner bit

Countersinking on the table saw with a forstner bit

Then the bit is swapped out, and holes drilled clean through the brace.

Bolt hole drilled through to come out centered on the flat of the brace

Bolt hole drilled through to come out centered on the flat of the brace

Install Braces

After staining, the braces are held in place and holes drilled with a long bit into the beam, then into the post. Long galvanized lag bolts are run in with an impact driver. Then hand tightened with a socket wrench to prevent thread rip out.

Installing smaller inside braces with lag bolts - pavilion

Installing smaller inside braces with lag bolts

The larger outside braces are easier to install with some help.

Larger outside braces go up with some help

Larger outside braces go up with some help

King Posts and Ridge Beams

Next we make the king posts and attach them to the beams with lag bolts.

King posts attached with lag bolts

King posts attached with lag bolts

The North/South ridge beam is brought up and laid across the East/West beams.

First ridge beam laid over East/West beams

First ridge beam laid over East/West beams

The last two king posts are secured then the ridge beam is lifted into place. Then a small corner brace is added between the king post and ridge beam.

Small corner brace added to king post and ridge beam

Small corner brace added to king post and ridge beam

Four rafters for the South and North gable ends will be installed. I put these in place now to help secure the ridge beam so it won’t move laterally when the next ridge beam is installed.

Laying out birds mouth cut on south facing gable end common rafter

Laying out birds mouth cut on south facing gable end common rafter

These rafters are cut to length and have plumb cuts on both ends. They are then positioned against the ridge beam and laid over the North/South beams to mark the birds mouth cuts.

I have a thing for screws. I'm sure nails are faster (and I have several nail guns) but I like the ability to adjust things as I go along

I have a thing for screws. I’m sure nails are faster (and I have several nail guns) but I like the ability to adjust things as I go along

They are secured to the beams with screws.

The king post on the East facing gable end needed some adjustment to ensure it was plumb and square before the next ridge beam was placed.

Setting the final ridge beam in place

Setting the final ridge beam in place

The shorter East/West ridge beam is hauled up and bolted into place.

Connor then stained the rest of the frame.

Gable end rafters on East facing end of pavilion

Gable end rafters on East facing end of pavilion

Valley and Jack Rafters

Next the valley rafters are cut. They have plumb cuts in either end and ideally a V groove cut in the lower end for fascia boards. Then an angled birds mouth where it sits over the intersection of the beams. And 45 degree angles cut in the upper end where it sits in the corner of the two ridge beams.

Four rafters are installed on the East facing gable end. Like the other gable ends, it’s done first to stiffen the structure before the next steps.

Valley rafter test fitting and marking birds mouth cut

Valley rafter test fitting and marking birdsmouth cut

Valley rafters are tricky and I have one chance to get them to fit right. So I took my time. I ended up hauling them up and down quite a few times before they were done and screwed into place.

Connor installed the common rafters across the West end of the pavilion at the same time.

Securing the peak end of the valley rafter to the intersection of the ridge beams

Securing the peak end of the valley rafter to the intersection of the ridge beams

With the valley rafters in place we called it a day.

Placing jack rafters between ridge beams and the valley rafter

Placing jack rafters between ridge beams and the valley rafter

Connecting the ridge beams to the valley are jack rafters. The ends are plumb cut square to their face where they connect to the ridge beams.

Underside view of all the rafters in place. Along with roof strapping

Underside view of all the rafters in place. Along with roof strapping

Then a plumb cut at a 45 degree angle where it mates with the valley rafter.

Final Framing

And that’s the principle framing done. Connor worked on his own to add fascia boards and all the roof strapping. Initially we planned to roll out tar paper over the strapping before adding the metal roof. Connor decided to use plywood instead.

Principle framing done for the pavilion structure

Principle framing done for the pavilion structure

He painted it flat black first before installing it and I think it looks great. It adds a nice contrast against the stained fir.

Flat black painted plywood over stained strapping

Flat black painted plywood over stained strapping

Three Gable Timber Frame Gazebo Pavilion

Three Gable Timber Frame Gazebo Pavilion

Three Gable Timber Frame Pavilion with black metal roof and trim

Three Gable Timber Frame Pavilion with black metal roof and trim

I came back to help finish the metal roof and add the trim. Later Connor plans to extend the deck to the North.

If you have any questions, please leave them in the comments below.

Thanks for reading

See also:  Shed Style Garden Pavilion

Tools Used

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Woodworking

Layout

Hardware

Adhesive & Finish

Drill Bits & Blades

Concrete Tools

 

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