Blocks for a feasibility study drawing

Feasibility is about testing questions, not answering them

The whole point of a feasibility drawing is speed of iteration, because you're usually trying to answer a handful of genuinely open questions, does the site fit the brief, can parking work, does a stair core fit where the client wants it, and every hour spent adding unnecessary detail at this stage is an hour not spent testing another option. I've sat in feasibility meetings where three or four site layouts got tested and discarded within a single working session, and that pace is only possible when the blocks in play are simple, fast to place, and fast to move.

So the discipline at feasibility stage is almost the opposite of construction detail work, resist the urge to make things look finished, because a feasibility drawing that looks too polished can actually mislead a client into thinking a decision is more locked in than it really is.

That pace is genuinely a competitive advantage too, since a client comparing two practices at feasibility stage often responds more to how quickly and confidently options were tested than to the polish of any single drawing produced.

Massing and site testing with generic blocks

For early site layout testing, generic representative blocks let you check whether a scheme physically fits before committing design hours to it. Does the parking count work with the required accessible bay included, use the wheel chair accessible symbol placed within a rough bay outline to confirm the count and general arrangement, not to finalise the exact bay position yet. Does a boundary access point work with a gate in roughly this location, drop an iron gate block in to test the swing clearance against a driveway or path before worrying about its final spec.

This is genuinely just about answering yes or no questions fast, can it fit, does it clash with something else, rather than producing anything that will survive into the next stage unchanged.

Multiple site layout variants can genuinely be tested within a single working session this way, moving the same handful of simplified blocks between two or three alternative arrangements and comparing them directly on screen or on a quick print, which is a pace of iteration that just isn't possible once detailed, fully dimensioned blocks are involved.

Testing vertical circulation options

Stair core position and configuration is one of the most consequential decisions tested at feasibility stage, because it affects structure, floor plate efficiency and often the whole massing strategy above it. Placing a circular stair block into a couple of different plan positions, checking headroom implications against a rough section, and comparing the floor area it consumes against a straight or dog leg alternative, is exactly the kind of fast comparative test feasibility work should be doing before anyone commits to detailed structural coordination.

Don't worry about exact going and riser figures at this point, the goal is confirming the stair fits the available footprint and headroom with reasonable confidence, leaving the precise dimensioning for schematic design once the general configuration is settled.

It's also worth testing the stair option against the client's actual functional priorities at this stage rather than just structural fit, since a circular stair might consume less floor area in one position but create a less intuitive arrival sequence than a straight flight in another, and feasibility is exactly the point in a project where that kind of qualitative trade off is still cheap to explore.

Access, paving and external works at a glance

External works rarely get much attention at feasibility stage, understandably, but a rough check of whether a driveway or path actually fits the available width alongside a boundary treatment is worth a few minutes, since discovering at construction stage that a required accessible route and a vehicle access genuinely can't both fit the site width is a much more expensive discovery to make late. A paving block dropped in at approximate width, even without a finished material spec, helps visualize whether the numbers actually work.

This is also a good moment to sanity check accessible parking and access together, since a scheme that works for able bodied access but genuinely can't fit an accessible route without expensive site regrading is exactly the kind of finding that changes a feasibility recommendation.

I'll often produce two or three quick variants of the external layout at this stage, one prioritising vehicle access, one prioritising the accessible route, and one attempting to balance both, purely as a visual aid for a client conversation about which priority actually matters more for their specific site, rather than presenting a single option as if it were the only possibility.

Keeping the drawing set light

A feasibility set typically stays small, a handful of sheets rather than a full drawing register, and the blocks you use should match that lightweight intent, simple representative symbols rather than fully detailed catalogue items. I keep a dedicated feasibility layer template with simplified versions of the blocks I reach for most, stripped of hatching and fine linework, specifically so early stage drawings stay fast to produce and fast to revise without dragging in the visual weight of construction ready detail.

It's worth resisting client requests to 'just make it look a bit more finished' at this stage too, since a feasibility drawing dressed up to look like a construction document tends to get treated as more final than it actually is, which can create expectation problems once real design constraints start narrowing the options.

When feasibility work earns out

At the end of the day a good feasibility study is measured by how many bad options it eliminates cheaply before real design money gets spent chasing them, and generic, fast to place blocks are the tool that makes that possible. The moment a scheme direction is confirmed and you're moving into schematic design, that's the point to start swapping in more considered representations, but not a moment before, because speed at this stage is genuinely more valuable than polish.

I think of feasibility work almost as insurance against the much larger cost of discovering a fundamental site constraint after schematic design hours have already been spent, and generic blocks moved quickly across a handful of options are the cheapest form of that insurance a practice has available.