Banks battered for working safety

Combination ring-beam & traditional Project Overview

This new basement was constructed using a combination ring-beam & traditional build approach. Beautiful Basements was asked to construct the basement including the waterproofing. The neighbouring property was very close on one side. This meant the full traditional build of a basement was not an option, instead a combination of a ring-beam and traditional build was required.

The neighbouring property was supported first with a ring beam. The second stage was to create the rest of the basement with a traditional open excavation build.

This ensured the structural integrity of the neighbouring property and a cost effective build for the clients.

Project Details

Categories:
Location: Leicester
Surface Area: 240 square metres
Completed: 2021
Architect: Design Studio Architects
Click here to see plans of the basement
Click here to see elevations of the basement

Stage 1 - Ring Beam

The combination ring-beam & traditional build basement started by supporting the neighbouring properties. This was carried out in two stages:

Creating the top section of the ring beam

Stage one was to support the neighbouring house by creating a ring beam. This beam is a reinforced concrete wall that prevents the ground collapsing and destabilising the foundations.

Once excavated, the foundations were supported with timber and struts. The first 1.2m of the wall was constructed with reinforcing steel, shuttered and cast with concrete.

Underpinning the top section of the ring beam

Once the first 1.2m had been supported, it was then underpinned in sections, to lower the support to 2.4m. This would eventually form part of the walls of the basement.

Once dug, the excavation was cleared out and a base concrete slab laid. This slab was linked to the wall via reinforcing steel. This steel would then link to the top section of the ring beam by more reinforcing steel. Eventually, when fully cast the basement walls had been formed and the neighbouring building and foundations had been supported.

Neighbouring wall supported during excavationShuttering for the ring beam is propped for concreteRing-beam is created with shuttering ready for concrete to be pouredShuttering proppedRing beam is cast and shuttering stripped, stabilising the neighbouring propertyRing beam underpinnedRing beam and floor reinforcedConcrete base under ring beam castUnderpins for ring beam cast with concreteCombination ring-beam & traditional build interfaceNeighbouring property supported by ring beam
Basement excavatedRing beam complete, basement excavatedTraditional open excavation buildBanks battered for working safetyExcavation linedBanks of excavation lined to prevent collapseBase compacted and blindedSteel reinforcing for traditional buildCombination ring-beam & traditional build interfaceTraditional build slab laid outTraditional slab laid with kickerFirst section of walls castSecond half of walls shutteredCombination ring-beam and traditional build linkedWalls castSteel reinforcing for traditional buildWalls shuttered & supportedWalls cast with concreteCombination build linkedTraditional wall built in two stagesCompleted wall constructionRing-beam underpins waterproofedFinal combination build tied togetherTie bar holes filled and waterproofedExternal sump chamberBasement excavation back filledBackfilling complete

Stage 2 - Traditional Build

Stage 2 – Traditional build

With the neighbouring properties supported, the rest of the build could take place.

Excavation & slab construction

The whole basement space was excavated to formation depth of around 3m. The formation base was blinded and compacted to give a strong base to work from.

Shuttering was used to form the outline of the slab and included a kicker upstand.  Click here for details of standard build construction

Reinforcing steel was installed and the ring-beam base steel linked into to the traditional build. Levelling rails we installed and set, and finally the concrete slab was cast.

Wall construction

When the slab was cured the walls were constructed in two halves to prevent cracking.

Shuttering was installed externally and then steel linked to the slab and kicker. With all steel installed, internal shutters were built, supported and finally the walls cast in concrete.

Once the first half was cast and concrete cured, it was stripped of shuttering and the second half constructed in the same manner.

Finally all shuttering was removed, tie bar holes filled and waterproofed and the basement backfilled ready for the next stage.

Take a look at some of our similar previous retrofit basement projects. Or click below to contact us and get a quote

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