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GBE Semi Basement (Brainstorm) G#7393

By 29 November 2015December 3rd, 2017Buildings, Collaboration, GBE Brainstorm, Projects, Services
Semi Basement Brainstorm

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GBE > Collaboration > Service > Brainstorm > G#7393

GBE Semi Basement Brainstorm

GBE Brainstorm Semi Basement

Site Location:

  • London N1


  • occupying space between terrace gardens to N and S


  • London
  • Urban heat island effect (UHIE) may have bearing on the site
  • London N1
  • UHIE may not be too intense
  • sheltered in the courtyard created by surrounding terraces
  • relatively less air movement than open streets
  • Terrace backs to north bathed in sunlight may increase temperature of air in courtyard


  • approx. 2 m wide gap between terraced houses,
  • 2 m wide alleyway to plot
  • Need for construction deliveries
    • Palletts on forklift attachment
    • 1m3 bags on forklift attachment
    • Hose for concrete
    • Deliveries will need some thought
  • Too narrow for car parking and pedestrian access?
  • Room for narrow car/van with sliding door?
  • Room for bike and motor bike parking
  • Room for waste segregation bins
  • Removable/movable bin and bike store construction?
  • Consider for other storage
    • (little provision in building)

Sub-soil conditions:

  • What are soil conditions?
    • London, probably clay, possible back fill in back land plot
  • What was previous use?
    • Sub-soil pollution issues?
  • Permeable pavement to minimise drainage requirements?
    • If clay less likely

Partially overhung

  • by mature deciduous trees to West and North
  • Tree root extent suggest piled/screw/auger foundation may be appropriate
  • But basement requires continuous wall and floor
  • Some disturbance to tree stability
  • Tree root water source may need compensation
  • Will new drain runs interfere with roots?
  • Flat roof needs easy access to remove leaves to avoid blockages every year

Canopy high enough?

  • to permit construction without some branches being removed
  • for air-flow and some summer evening solar penetration
  • Autumn leaf loss will permit limited winter evening solar penetration

No section through block:

  • so no knowledge of summer-solstice-winter morning-midday-evening solar access solar penetration


  • semi-buried long strip, no windows in basement, light wells (see below)
  • will require insulation from ground or potential occasional anti-condensation heating in summer
  • 2 southerly high windows to upper floor (Living/dining/kitchen & Wetroom) on boundary
    • Are restrictions imposed: ventilation opening? Opening casement projections?
  • courtyard voids at both ends serving basement via full height sliding or folding doors

rooms to basement courtyards:

  • West end east facing:
    • Plant (potential heat and noise source)/
    • Gym (humidity source),
  • West end west facing
    • Bedroom (humidity source)
  • East end east facing
    • AV room (Potential heat and noise source)
  • Light surfaced courtyard may generate AV luminance problems
  • Working in kitchen will cast shadows on activity
  • Consider light pipe or borrowed light from stairwell

Rooms to upper floor of courtyards:

  • East end east facing:
    • Bedroom (humidity source)
  • West end west facing
    • Living, dining and
    • kitchen (Potential heat, humidity, smell source)
  • Roof and upper floor indicated as having no down-stand lintel or beam
    • Permitting easy removal of heat from rooms

Roof is flat with small parapet:

  • Roof light over stairwell?
    • Ventilation opportunity?
  • If there is solar access to flat roofs:
    • Then need to protect from overheating
    • By solar resistant high decrement delay building fabric or insulation

Basement construction:

  • Basement walls:
  • Likely to be insitu concrete or reinforced concrete block wall, internal insulation and internal drained tanking, (ineffective thermal mass in walls)
  • Not dimensioned but greater than the 300 mm. upper walls

Basement floor:

  • No information (any thermal mass in floor finish?)

Upper floor:

  • Shows thin construction no down-stand beams and no lintels
  • Probably Spanning N-S
  • No E-W large service routes
  • Could benefit from thermal mass

Upper wall construction:

  • Indicated as 300 mm thick (insufficient) unless timber framed and fully filled with insulation
  • If solar access is present:
    • Then need to protect from overheating
    • By use of solar resistant high decrement delay building fabric or insulation


  • Shows thin construction so beams if any are within roof thickness
  • If solar access is present:
    • Then need to protect from overheating
    • By use of solar resistant high decrement delay building fabric or insulation

WC projection on north elevation upper floor:

  • Is it cantilever over site?
    • Will loose heat from large surface area
  • May well be relatively cold and potential condensation risk
    • Consider wet room as offsite pod with WC included

Internal basement wet room:

  • Requires passive, active or mechanical ventilation consider heat recovery.

Water delivery and sewage/waste disposal in 6 locations

  • Courtyards, Garden, Kitchen, Wet room, WC, Bathroom may be complicated and expensive
  • No ducts or routes indicated: Floor and roof are likely to span from N-S so no E-W routes

Drainage of flat roofs:

  • 1 RWP indicated in adjacent plot to North
    • permission required/obtained?
  • Could drain into courtyards to avoid water supply there
  • Consider rainwater harvesting and permeable pavement.

Clothes Drying:

  • Small kitchen unlikely to make provision
  • 1 Garden, 1 alleyway, 1 covered access and 2 courtyards can make ample secure provision.

© GBE NGS ASWS BrianSpecMan aka Brian Murphy
26th November 2015 – 1st December 2015

GBE Semi Basement Brainstorm

GBE Brainstorm


GBE Brainstorm LondonN1Semi-Basement Issue 1
Text in left column is more up to date


F132Basements PDF

GBE Robust Specification

Safeguard Basement Tanking Systems

© GBE NGS ASWS BrianSpecMan aka Brian Murphy
26th November 2015 – 3rd December 2017



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