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Saddle roof picnic shelter

Waterproof membrane design concept

A proposed permanent membrane roof using Tenseo Advanced 1002 S2 as the fabric reference. Intended for U.S. areas without heavy snow. No wind, snow or foundation rating has been established.

Revision 36 stepsadvanced
Before you start
  • This is a design concept for viewing and further development, not a construction plan. Do not use these files to order, cut, erect or tension the shelter.
  • The roof geometry and reference timber frame are modeled, but their load capacity, connections and foundations have not been established. Areas without heavy snow can still require wind, rain and snow design.
  • An accepted membrane/fabricator specification, biaxial properties, installed tension, compensated cutting patterns, qualified seams, clamps and weather seals are required before fabrication.
  • Supporting beams extend below the 7 ft 6 in low membrane reference, reducing clear headroom. The CAD envelope is 1 mm thick for display; the reference product sheet states 0.78 mm.
  • The roof area and component inventory are geometric quantities. Actual shopping and cutting lists are unavailable.
Dimensions and opening sizes
Outer beam triangle, each sideThe roof ends at this equilateral triangle; no eave extension is included.
40 ft
Post spacingThree post centers form an equilateral triangle.
20 ft
Lowest roof heightAbove grade. Beams extend below this level, reducing headroom.
7 ft 6 in
Roof height at outer cornersAbove grade.
11 ft 6 in
Roof height at centerAbove grade.
17 ft 6 in
Curved roof areaExcludes seams, hems, reinforcement, overlaps, fitting allowances and waste. Do not use this as an order quantity.
72.606 m²
Shopping list

Real shopping and cutting quantities depend on the engineered membrane, connection system, frame and foundations. The provided inventories contain modeled geometry only.

Tools & equipment
  • FreeCAD or a compatible STEP viewer for geometry inspection
  • Blender for scene editing and rendering

BEFORE YOU BUILD

Use this work at your own risk

No person or organization makes any guarantee or warranty, express or implied, regarding this design, its documentation, digital files, or website views. They are not professional services and do not create an architect-client or other professional-client relationship. No promise is made about accuracy, completeness, reliability, code compliance, or fitness for your project.

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CC CC BY-NC-SA 4.0 InternationalShare and adapt this free design for noncommercial purposes with appropriate credit. Link to the license, indicate changes, and license adaptations under the same terms.

Instructions

Dimensioned envelope plan and elevation with seven labeled control points, post locations and roof heights.
Envelope plan and elevation with node labels, 40 ft outer triangle, 20 ft post spacing and reference roof heights. These are development dimensions.
Top view of a triangular membrane roof divided into three panels around a central crown.
Top view of the three roof sections. Use the dimensioned drawing for measurements.

01 Read the triangular layout

  • Use the dimensioned plan to locate the three posts and seven envelope nodes. The outer triangle has 40 ft sides and the post triangle has 20 ft sides. These are nominal model dimensions.

Check: Identify the three low attachment nodes and distinguish the outer triangle from post spacing.

Three-post timber picnic shelter with three smooth white saddle-shaped roof sections meeting at a raised central crown.
Three posts support the roof, leaving the center open.
Reverse view of a white three-panel membrane canopy on three timber posts.
The three fabric roof sections meet at the raised center.
Front elevation of the membrane shelter, with a tall center crown, two raised corners, three timber posts, and exposed footings.
Front view with the central peak, raised outer corners and buried footings exposed.
Side elevation of the shelter showing curved membrane panels above the timber frame and exposed footings.
Side view of the roof and timber supports. Footings are shown below ground level.

02 Compare the roof views

  • Compare the overall, reverse and elevation views. Three saddle-shaped membrane assemblies meet at the central crown. The low roof reference is 7 ft 6 in, outer corners are 11 ft 6 in and the crown is 17 ft 6 in above level grade.

Check: Locate the crown, three raised outer corners and three low attachment points in the views.

Low view beneath the white canopy showing the three timber posts, sloping crown beams, and perimeter beams.
Timber beams extend below the fabric, reducing clear headroom.
Three timber posts with sloping beams, roof attachment strips and exposed concrete footings.
Fabric and ground hidden to show the frame and footings. These supports still require structural design.

03 Inspect the exposed frame

  • Use the underside and frame views to see the beams below the fabric and the three foundations. The drawing exposes buried footing regions for explanation. These inherited supports require structural design for membrane loads.

Check: Distinguish the reference frame and footing geometry from an engineered support specification.

Close-up of a timber post cap and sloping beam connection beneath the membrane edge.
Proposed post, beam and roof-edge connection. Fasteners, load capacity and weather seals must be designed before fabrication.

04 Understand the proposed attachment

  • The connection view shows the intended location of continuous edge clamps and post/beam connections. The bands are schematic zones, not dimensioned rails or tested joints. Crown closures, reinforcement, fasteners and watertight details remain undeveloped.

Check: Recognize which illustrated attachments are placeholders for further design.

Dimensioned envelope plan and elevation with seven labeled control points, post locations and roof heights.
Envelope plan and elevation with node labels, 40 ft outer triangle, 20 ft post spacing and reference roof heights. These are development dimensions.

05 Use the matching design files

  • Open the native CAD for direct geometry inspection, STEP for exchange and Blender for rendering. Stored control points and display thickness do not parametrically regenerate the solids. Read the seven-page guide and geometric inventories together.

Check: Confirm the files are for this three-assembly membrane concept and that inventory rows are not purchase or cutting instructions.

Three timber posts with sloping beams, roof attachment strips and exposed concrete footings.
Fabric and ground hidden to show the frame and footings. These supports still require structural design.
Close-up of a timber post cap and sloping beam connection beneath the membrane edge.
Proposed post, beam and roof-edge connection. Fasteners, load capacity and weather seals must be designed before fabrication.

06 Plan the engineering needed to build

  • Before construction, obtain accepted fabric data and a numeric site/load envelope, then coordinate membrane form-finding, frame and foundation design, fabric patterns, drainage and installation details. Only the completed coordinated design can supply actual shopping and cutting schedules.

Check: Do not begin fabrication or construction from this concept package; identify the required membrane fabricator and structural design work.