Floors

Floors

1. What is a floor?

   • horizontal structural platform upon which activities can be performed within a building
   • Defined as the final wearing surface or material applied on top of a structural floor
   • Span perimeters walls whilse upper floors often overarch intermediatry load-bearing walls retaining support between steel hangers fixed directly over internal walls

2. Functional Requirements

   • Strength & Stability
     • a slab should remian strong enough to deal with live and dead loads without deflecting to cause structural damage to elements such as plaster and surface coatings
   • Resistance to damp & ground moisture
   • Adequate thermal insulation
   • Adequate fire safety
   • Durability & Freedom from maintenance
   • Adequate sound insualtion
   • Adequate resistance to the passage of gas
   • Act as ties (acting in tension) at all times to ensure the walls do not suffer excessive bulking as a result

3. Concrete Ground Bearing Floor

   • Overview
     • solid slab
     • insitu base
     • constructed independent of walls
   • Sulfate attacks
     • During 1945 and 1970 sulfate bearing hardcore from spoil or demolition debris containing gypsum plastic was used as a support for concrete floors wihtout a DPM
       • This led to...
         • damaged floor slabs
         • cracking and expansion
     • water must be required if this is to become an issue
     • Types of sulfates
       • Gymsum
         • Calcium carbonate CaSO4
       • Epsomite
         • Magnesium sulfate MgSO4
       • Glaubers salt
         • Sodium sulfate Na2SO4
     • Results
       • dooming/ cracking/expansion
     • Soltuion
       • Sequence
         • Dig out floor well below OGL
           • Remove original hardcore
             • Replace floor wiuth mix
               • Compact the hardcore with a Wacker Neuson Plate in layers not exceeding 150mm
                 • New sand blinding layer compacted top remove air
                   • New DPM all joints taped over
                     • Floor insulation cut & installed
                       • New concrete floor slab (SRPC)

4. Timber Flooring

   • Timber bearers comprise of...
     • Softwood battens 47mm wide by 1800mm long with foam strip 9mm thick under