- Light green wooden joists
- Level fixings
- The framework
- Protection and finish
- Mechanical links
- Determine the location of metal hooves
- Drill the holes
- Fix with pegs and lag bolts
- Sand the faces of the woods
- Identify the location of the joists on the beams
- Prepare the recessed areas with the saw
- To cross shaded areas
- Finish the job at the router
- Treat the wood and apply the paint
- Install the main beams
- Drill guide holes
- Drill blind holes and install the joist
- Fix the joists to the beams
Some beams and joists, paint and fixtures were enough to build this pergola that can be dismantled at the end of the beautiful days, and stored in the shelter while waiting to resume service.
This pergola very simple to build requires only few materials, accessories.
To achieve this, purchases at Gedimat are summarized as follows:
- 3 beams (7.5 x 17.5 cm in 4.50 m, 59.40 €),
- 14 joists (5 x 15 cm in 2 m, 76 €),
- 6 mixed clogs with inner wings (13,50 €),
- a bag of 50 lag screws Ø 8 x 50 mm in galvanized steel (7,30 €),
- a box of 25 pegs S 12 (€ 4.72),
- a pot of 2,5 l painting "Abribois" satin olive green of Ripolin (52,90 €)
- and a bed screw pocket, € 9.80 at Leroy-Merlin.
Light green wooden joists
The pergola is logically installed in a "corridor" delimited by the southern gable of the house and the retaining wall of a garden on a hillside. In a very simple design, the supporting framework consists of three parallel main beams whose ends rest in metal shoes fixed in the masonry of the two walls in vis-à-vis. They take two rows of seven joists resting in notches every 50 cm. The set is covered with a light green wood paint and remains easily removable to spend the bad season sheltered from the weather.
When the support allows it, here the pinion and the retaining wall, the metal hooves are the best solutions to support beams. Available in different sizes depending on the section of the parts to support (7.5 x 15 cm in our case), they also have various profiles to adapt to the configuration of the support.
In stainless steel, the metal shoes are leveled at 2.30 m above the ground. Spaced 1.95 m, the first three are fixed on the gable wall by drilling the masonry with a concrete drill ø 12 mm. Each shoe is held by four lag screws (Ø 8 x 50 mm), screwed into ø 12 mm plugs.
The operation is repeated with the installation of the hooves vis-à-vis on the opposite wall. A laser level is here very useful and practical. If you do not have one, draw from the hooves set vertical to the ground. Post these lines on the ground, checking their squareness to the wall opposite. Trace verticals again and locate the hoofs.
Its assembly is done mid-wood. The joists of 5 x 15 cm section rest on the beams of 7.5 x 15 cm thanks to cuts (of 20 mm of depth, 130 mm of height and 50 mm of width) practiced in these last. This work is done without difficulty. The beams and joists delivered "rough sawn" are first planed on their four sides.
After postponement of the distance measured between the shoes facing each other, the three beams are sawn to length. They are then placed on edge and side by side to transfer conveniently and accurately, every 50 cm, the locations of the notches of the joists. These are made with a circular saw set to a depth of 20 mm and then trimmed with a chisel. To eliminate imperfections of roughing, the flatness of the bottom and the sides of the cuts is rectified with a router-mounted milling cutter.
The beams are placed in white in the hooves to determine the length of the joists, which are identified one by one and cut to measure. The last cutting operation is a notch made at the ends of the joists on their lower part. On one side, trace and cut a small square of 20 mm.
All the wood is left on edge to be molded with a quarter-round milling cutter on their upper edges, a shape that will facilitate the evacuation of rainwater and prevent their stagnation.
Protection and finish
An insecticide, fungicide and water repellent treatment for "wood and exterior structures" is painted in two or three layers on the beams and joists. It is imperative to insist and ensure a good impregnation of the product at the ends and at the level of the assemblies. Rainwater can stagnate and seep into it if it does not evaporate or does not wash off quickly.
After drying the treatment product, about forty-eight hours, an exterior wood paint is applied. Microporous, allowing the wood to breathe, it is applied in two or three layers. The first, diluted according to the indications of the manufacturer, acts as primary. After drying, a fast sanding with sandpaper (grain 80) precedes the application of the second or even the third layer of paint.
Removable, the frame of the pergola is not fixed. The dimensional variations of the wood can however cause a dislocation of joists weakly embedded in the beams. To maintain the demountable appearance of the structure and provide some security, mechanical fasteners are made between the central joists and beams. Easy to tighten and loosen, reminder screws, called beds, are used. Common, they consist of a screw and a blind nut.
In the middle of each beam, a hole is drilled in front of a central joist. Then a second in the end thereof in which is housed the blind nut. The screw goes through the beam and comes to tighten. These adjustable mechanical fasteners are sufficient to compensate for the dimensional variations of the wood and to keep the framework in place.
Determine the location of metal hooves
With a rotating laser level, it is easy and quick to draw a mark on the two opposite walls to accurately determine the lines on which will align the metal shoes.
Drill the holes
Trace the location of the hooves, here a spacing of 1.95 m. Place one of them blank to locate the fixing holes, four at least. Drill with a drill equipped with a drill 12 mm in diameter.
Fix with pegs and lag bolts
Insert dowels into the holes. The metal brackets support beams are internally padded for better aesthetics. Secure them with stainless steel lag screws (Ø 8 x 50 mm).
Sand the faces of the woods
If the wood is "sawn rough", plan the four faces in two passes, three at the sharpest kerf marks to obtain a good surface finish for painting.
Identify the location of the joists on the beams
Using a square, trace on the side of each beam the section of joists, 5 cm wide by 13 cm high. On the central plank, locate on each of the two faces.
Prepare the recessed areas with the saw
Some saw cuts prepare the notches of the recesses which will receive the end of the joists. Set the cutting depth of the saw to 20 mm. Saw inside the lines of the hatched area.
To cross shaded areas
With a sharp wood chisel and mallet, blow out the pre-cut pieces with the circular saw. Roughen the notches of the beams, taking care not to exceed the shaded area.
Finish the job at the router
For perfect embedding, finish off the sides and bottom of the cutouts with a reamer equipped with a straight cutter (Ø 14 mm or more). This will remove imperfections from roughing work.
Treat the wood and apply the paint
Apply a fungicide, insecticide and water repellent treatment to all woods, emphasizing the ends of beams and joists, and notches. Then put two or three coats of wood paint.
Install the main beams
Let the paint dry before placing the three beams in their respective metal shoes, previously painted too. Attention to weight! Handle the planks to two people.
Drill guide holes
In the middle of each beam, drill from the inside to the outside, in the center of the notch to receive the joist, a hole 9 mm in diameter to guide the bed screw.
Drill blind holes and install the joist
After identification, the joist is placed in its notches and marked with a screwdriver passed through the guide hole of the beam. Drill a Ø 25 mm blind hole at the ends of the joist.
Fix the joists to the beams
Screw the nut into the blind hole and repeat the previous operations on the other two beams and the corresponding joist ends. After installation, screw without tightening.