Constructing your drawings(the role of the section)

Building components used in modern construction are not uniform i.e. uniformly filled(designed). There are objects that may have 'detailed' features(holes, grooves, recesses, protrusion, etc.). These details can (only, can't be only) best be shown shown with a sectional view (especially when the drawings are in 2 dimensions) and makes it an essential or rather important detail in construction drawing.

A 'section drawing', 'section' or 'sectional drawing' shows a view of a structure as though it had been cut along an imaginary plane which is referred to as “cutting plane”. Plan drawings are in fact a type of section, but they cut through the building on a horizontal rather than vertical plane.

Cross section drawings show views of the home as though you had sliced  through the house from the top with a saw and looked in from the resulting opening. This view will help the builder better understand your interior and exterior construction details.

When designing or representing structures (buildings) it gives a view that passes through spaces such as rooms and also through the building fabric, and this can reveal relationships between the parts of the building that might not be apparent on plans or elevations.

Majority of private clients on this side of world can actually afford but are not always willing to pay the professional charges to produce a detailed working/construction drawings as the case may be. This has in time over the years makes majority of buildings to lose forms and shapes or clearly deviating from the initial preconceived performance briefs provided.

If drawings will lack a back up specification writing and finishing schedule, then the least that is expected is to have our building sections comes with more (appropriate) details that will aid construction. The more complex the home design, the more cross sections you should provide. I have said it so many times, that the basic requirements of minimum of two sections as a basis for all buildings more than one floor going for construction approval at the local planning authorities has made so many Architects more lazy. (maybe you should consider the fact that planning drawings are not necessarily construction drawing, the constructor/builder is therefore at liberty to require as many sections as he requires to construct). As shown below, the proposal require not less than the amount of sections(6nos) made available if not more.

Because of some of the duties sections are meant to perform which are not limited to what is being highlighted in the next paragraph, an average 5bedroom duplex design will need not less than four sections to make such documents useful for construction to be done the way you had conceived without you being charged to supervise such construction. An average builder should be able to understand the basic things and ideas you intend to implement from your sections.

These drawings are used to show such things as wall and roof framing details, exterior wall layers, stair construction and even interior details such as variances in floor and ceiling heights, soffits, moldings and cabinetry. Cross sections also show window details such as dimensions, exact locations with respect to interior walls and their heights relative to the ceiling or floor. Cross sections in general do not show finished wall or flooring materials aside from sections that specifically detail wall or floor layers.

Thanks to Arc. Moyosade Adesibikan for the wonderful review and editing of this blogpost.