Table of Contents
This pergolaA structure with open wood-framed roofs, often latticed and supported by regularly spaced posts or columns, and covered by climbing plants such as vines or roses, shading a walk or passageway. Pergolas are distinguished from “arbors,” which are less extensive in extent and structure. is called the ‘box’ pergola because it is built with rows of solid blockings/nogs between the rafters forming rows of square or oblong boxes. This type of pergola is becoming increasingly popular and is relatively easy to build.
Material
| <spanThe horizontal distance between supporting structures.>MATERIAL | AMOUNT |
| 150×50 (2×6) treatedPressure treated. Refers to lumber that is treated in such a way that the sealer is forced into the pores of the wood. Refers to lumber pressure sprayed with chemicals to lengthen its life expectancy for outside use or inground applications. lumberAny of the framing wood. rafters, blockings/nogs and decorative ends | 30 metres (100 ft) |
| 200×50 (2×8) treated lumber beamA supporting member. | 3.6 metres (12 ft) |
| 100×100 (4×4) treated lumber | 7.2 metres (24 ft) |
| 1kg (2.5 lb) gal 90mm (3 1/2″) nails; 20 galvanizedCovered with a protective coating of zinc. nailA short nail with a large flat head used for securing roofing felt, plasterboard, sheet metal to wood etc. plates; 8 12mmx120mm (1/2″x 5″) galvanized coachAre round headed bolts with square shoulders that resist rotation when located or driven into place. They can be called coach bolts or carriage bolts depending on which part of the world you live in. The head end of the bolt does not need a washer, but the other end of the bolt (the nut end) usually does./carriage bolts, 2 bags concreteA mixture of sand, gravel, water and cement which hardens to a stone like condition when dry. mix |
About the lumber
All the lumber used in this project is treated dressedSurfaced; planed; smooth; even surface; gauged./surfaced pine. The posts are treated for in ground applications. and the rest of the structure is treated for outside use. All the lumber that is used in this project is readily available at most lumber merchants.
The lumber sizes referred to in this project are the nominal sizes. The nominal sizeThe rough-sawn size of a piece of lumber. Before the lumber is surfaced, planed or dressed. The nominal size is usually greater than the actual dimension. e.g. 100x50 (2 x 4) actually equals 90x45 (1 1/2" x 3 1/2"). of a piece of lumber is the size of the lumber before it is dressed or seasoned and is the size generally referred to when purchasing from the lumber yard. The actual sizeThe finished (dressed) size as opposed to the nominal size of a piece of wood., or dressed size of the lumber will be less than the nominal size so please make necessary allowances. For example, a piece of 100×50 (2×4) lumber when dressed may be 90×45 (1 1/2″x 3 1/2″) actual size.
The Plans.
The plan view (birds eye view looking down), the front view plan and the side view plan.
The Posts, beams and rafters.
The bottoms of the posts are bolted to the deckA flat floored roofless area adjoining a house. Timber deck: An outside floor structure comprising of posts, bearers, joists and decking boards. joists or the deck boundary joistOne of a series of parallel members used to support the floor. Part of the framing that provides the structure for a floor. and also concreted into the ground. The ledger plateThe top or bottom horizontal framing member of the wall. (also called stringer) is bolted to the house wall above the doorA horizontal framing member above the door/window opening., The top of the posts are checked out to accommodate the beam and the rafters are nailed in place between the ledger and the beam.
A square hole (postsee PILE size) is cut in the decking. The posts are placed through the hole in the decking and into a hole dug in the ground. The bottoms of the posts are bolted to the deck joists or the deck boundary joist and also concreted into the ground. (See drawing below).
The roof structure
The ledger plate (also called stringer) is bolted to the house wall above the door with 12mm (1/2″) galvanized screws every 900mm (36″) apart. There is (in most cases) a lintelHeader; A beam placed perpendicular to wall studs above doors, windows or other openings to carry the weight of structural loads. (beam) above all doors, thus ensuring solid fixing. The height of the ledger plate determines the overall roof structure height.
The required heights of the top of the posts are obtained by levelling across from the top of the ledger plate .
The top of the posts are rebated/checked out to accommodate the pergola beam. Refer to image below.
The beam is bolted in place. see the plans for dimensionsAny of the three linear measurements, length, breadth and depth.
The rafters are nailed in place between the ledger and the beam. See the plans for dimensions
The Nogs and Decorative RafterStructural member of a roof that supports the roof load and runs from the ridge to the top of the side walls. Ends.
The nogs:
The rows of solid nogs or blockings are placed and nailed between the rafters. See the plans for dimensions
The decorative ends:
The decorative ends are a continuation of the rafters and the rows of solid nogs/blockings. They are secured in place with 2 90mm (3 1/2″) galvanized nails skewed, toe nailed through the lower part of the decorative ends and with nail plates fixed on the top edge. (see drawing)
The rows of solid blockingBlocks, see Block./nogs are placed and nailed between the rafters and the decorative ends are fixed in place.
Securing the top together.
The pergola roof structure is locked together by fixing galvanized nail plates on the top edges of the rafters, blockings/nogs and decorative ends.
The Finish.
All done. Eazy with a Z !
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