Add a covered porch or balcony

The Porch / balcony tab in the Build generator creates an open addition with posts and a gable roof. Choose the platform’s floor, projection and position, then configure its posts, beams, decking and railings.

Add and position the porch

Choose Add porch / balcony, then select roof side A or B, width, projection, centre from the left and Platform floor. With two storeys, the upper floor is selected by default. Hover or focus the ? controls for help.

The roof eaves follow the main roof. The platform’s joist tops follow the selected storey’s floor joists, and the flat ceiling follows the soffit underside. On a two-storey building, choosing the first storey creates a porch with a double-height ceiling beneath the main eaves.

The width is the outside platform width. Rafter seats follow the configured side beams, so changing post or beam dimensions keeps the roof seated on them. Both side eaves and the front gable overhang have soffits. They use the main soffit finish when available, otherwise the porch ceiling finish. Disabling the flat ceiling leaves the overhang soffits in place. Perimeter trim closes any gap between the aligned ceiling and the support beams. The ridge cap follows the porch roof apex, including short projections and porches whose pitch differs from the main roof.

The designer preview uses the same roof pattern as the main building. Its gable sits behind the roofing, and solid railing members meet the posts without lines showing through them. Support beam corners stay beneath the roof outline at both eaves. Changing railing sizes, infill or entrance gaps updates the preview before generation.

Choose a platform or roof with posts

Include balcony / porch floor is on by default. Turn it off to retain the roof, gable, ceiling, soffits and roof beams above continuous support posts. The platform framing, decking, railings and balcony separator wrap are omitted. Posts extend from their configured base to the roof beams.

Floor and railing controls hide while the platform is off. Their settings are retained and return when you enable it again. The building’s own separator stays on the main wall.

For a separate ground-level slab or timber deck, expand Entrance / terrace. It is off by default and can sit below an upper balcony or under a roof with posts. See entrance slabs and timber terraces for shapes, level, supports, a front step and mouse resizing.

Finish the gable and separator boards

For an upper-floor balcony, enabling the building’s Separator board also wraps it around the balcony sides and front. Its profile, dimensions and finish match the building, with mitred corners and wall returns. The board top follows the floor joist top, below the decking, even when Outer floor beam is off. Ground-floor porches leave the upper-floor board on the main wall.

Open Gable siding to change the front gable finish. It uses a simplified panel and follows the main roof storey’s siding by default. Turn off Match main building siding to choose horizontal, vertical, shiplap or smooth siding, set the board/course width and panel thickness, or disable siding on this gable. These settings are independent of the balcony’s selected floor and remain saved with the design. Return to matching to follow the main building again. The generated gable siding meets the sloping front soffit boards. Its bottom is one straight edge at the horizontal soffit underside across the full width; it does not step down over the posts when beam depth changes. Horizontal soffit ends stop at the back of the siding. Enable Textures in the Build generator to give it the default wood finish; disable it for plain siding. Regenerate an existing building to apply the updated fit.

On a two-storey building with a separator board enabled, Gable siding also offers Use separator board on roof front. This decoration is off by default and requires gable siding. It inherits the building’s flat/capped profile, dimensions and finish, with its bottom flush with the siding bottom and both ends bevelled to the gable slope. It works with or without the balcony platform and is independent of the separator wrap at floor level.

Posts, deck and railing

Outer floor beam under Floor & decking is off for new porches. Turn it on to add the beam beneath the front floor joists. Lower posts meet the floor when it is off; the rim and configured side beams remain. Existing saved designs keep their beam until you disable it and regenerate the building.

Front posts are equally spaced by default. Change their count and width/depth, or enable manual centre positions measured from the left edge. Extra side posts and beam dimensions have separate controls. The post base elevation can be set relative to the model origin.

Floor controls set joist size and maximum CC, decking thickness, board width and gap. Railings can be enabled on the front and either side. Choose vertical or horizontal infill and adjust the height, member sections, spacing and entrance. Keep support posts clear of the railing entrance.

Doors and existing framing

Add entrance and balcony doors in Openings, just as on the main building. Choose the correct storey. Dashed deck and post references help with placement; a porch never inserts doors automatically.

The main walls, rafters/trusses and roof sheathing stay intact. The new roof is framed over the host roof. The host roof covering is trimmed at the junction through to the eave, so no concealed roofing strip crosses the porch interior. Regenerate an older model to apply this correction. This works with the gable beam/collar-tie, saved W-frame and A-frame, and Hip roof paths. Enable roof sheathing and walls before adding a porch. Keep its roof clear of hips, the ridge and other additions.

For an enclosed room that opens through the main wall, use the existing Building extension placement in Dormers. Covered porches have their own settings and do not change ordinary dormer or extension behavior.

Working designs, drafts and .strek project files retain the porch settings. Generated members appear in groups, quantities and the build timeline.