Typical Imposed Loads for Residential Buildings

Typical live loads of different types of buildings. Handy information for civil or structural engineers.

Self contained dwelling units;   1.5 kN per meter squared.

For public buildings where there is a tendency for many people to be in the building at once. For example;boarding houses, lodging houses, guest houses, hostels, residential clubs and communal areas in blocks of flats Boiler rooms, motor rooms, fan rooms and the like including the weight of machinery;  7.5kN per meter squared.

Communal kitchens, laundries;  3.0kN per meter squared.

Dining rooms, lounges, billiard room ; 2.0kN per meter squared.

Toilet Rooms; 2.0kN per meter squared.

Bedroom, Dormitories; 1.5kN per meter squared.

Corridors, hallways, stairs, landings, footbridges; 3.0kN per meter squared.

 Hotels and motels Boiler rooms, motor rooms, fan rooms and the like, including the weight of machinery ;  7.5kN per meter squared.

Assembly areas without fixed seating, dance halls, Bar; 5kN per meter squared.

Assembly areas with fixed seating;4kN per meter squared..

Corridors, hallways, stairs, landings, footbridges, etc; 4kN per meter squared..

Kitchen Laundries; 3kN per meter squared.

Dining rooms, lounges, billiard room; 2kN per meter squared.

Bedrooms., Toilet rooms ; 2kN per meter squared.

Strength of Common Building Materials

Building materials

Here are strength of some common building materials based on BS 648. This is useful information for civil/structural engineers

Asphalt 

Roofing 2 layers; 19 mm thick,  42 kg per meter square.

Damp-proofing; 19 mm thick, 41 kg per meter square.

Roads and footpaths; 19 mm thick 44 kg per meter square.

Bitumen roofing felts 

Mineral surfaced bitumen;     3.5 kg per meter square.

Blockwork 

Solid per 25 mm thick stone aggregate ;  55 kg per meter square.

Aerated per 25 mm thick;        15 kg per meter square.

Board

Blockboard per 25 mm thick;   12.5 kg per meter square.

Brickwork 

Clay, solid per 25 mm thick;     55 kg per meter square

Medium density Concrete, solid per 25 mm thick;   59 kg per meter square.

Cast stone;  2250 kg per meter cubic.

Concrete 

Natural aggregates;   2400 kg per meter cubic.

Lightweight aggregates (structural); 1760 + 240/ −160 kg per meter cubic.

Flagstones 

Concrete 50 mm thick;   120 kg meter square.

Glass fibre 

Slab, per 25 mm thick; 2.0–5.0 kg meter square.

Gypsum panels and partitions 

Building panels 75 mm thick;    44 kg meter square.

Lead 

Sheet, 2.5 mm thick;    30 kg per meter square.

Linoleum 

3 mm thick; 6 kg per meter square.

Plaster

Two coats gypsum; 13 mm thick;    22 kg per meter square.

Plastics sheeting (corrugated);   4.5 kg per meter square.

Plywood

per mm thick;    0.7 kg meter square.

Reinforced concrete;     2400 kg meter cubic.

Rendering 

Cement: sand (1:3), 13 mm thick;   30 kg per meter square.

Screeding 

Cement: sand (1:3), 13 mm thick; 30 kg per meter square.

Slate tiles 

(depending upon thickness and source);  24–78 kg per meter cubic .

Steel 

Solid (mild); 7850 kg per meter cubic.

 Corrugated roofing sheets; 10 kg per meter square per mm thick.

Tarmacadam ;

25 mm thick 60 kg per meter square.

Terrazzo; 

 25 mm thick 54 kg per meter square.

Tiling, roof 

Clay; 70 kg per meter square.

Timber 

Softwood;  590 kg per meter cubic .

Hardwood; 1250 kg per cubic meter.

Water; 1000 kg per meter cubic.

Woodwool

 Slabs; 25 mm thick 15 kg per meter square.

Note: to convert to Newtons per millimeter square; Multiply the amount in kg by 10 and then divide by 1000

Road Construction Within Housing Estate

estate road

Road construction  within a housing estate is necessary to provide standard access road and driveways into private dwellings. This type of road construction  is on a small scale. The construction of these types of roads will be discussed under three aspects;

  1. Setting out
  2. Earthworks 
  3. Pavement construction.

Setting out

Setting out means the establishment of center, width, existing level and formation level of the road. This activity is usually carried out after top soil removal. The layout can include straight lengths, turning bays and intersection curves. Drainage positions must  be adequately set out as well.

Road center  points, widths and levels can be set out using traditional methods with the aid of levelling instrument/ theodolite/ total station, ranging rods,levelling staff, measuring tapes, pegs, markers and so on.

Earthworks

 After proper setting out has been done. Existing  and formation levels, determined and marked out, earthworks can begin. Earthworks involve the movement of earth to and from sections of the road in such a way that the formation levels/ design levels of the road is achieved. This process is also carried out for the road’s drainage as well.

Pavement construction 

The earthworks prepare the subgrade. Once drainage and other buried services have been installed, pavement construction can commence. There are two types of pavements; flexible and rigid pavements.

Flexible pavements consist of materials that are applied in layers over the subgrade. Rigid pavement consist of concrete slab resting on to of a prepared subgrade the construction of flexible pavement should consists of the following layers.

Section of a typical flexible pavement

A sub base layer of about 100mm thick on the subgrade. The sub base can consist of crushed stone or dry lean mix concrete followed by a surfacing layer of asphalt which can be around 60mm thick.

Concrete

wet concrete

Concrete is a mixture of water, sand, stones and cement. It hardens to a stone like mass within a few days. Concrete  is highly strong and durable with a life span of about 50yrs.

Concrete is a major constituent of modern building structures. Many houses, roads,bridges, skyscrapers are constructed using concrete.

Grade of Concrete

Grade of concrete refers to the strength and quality of concrete. The grade of concrete typically depends on;

  1. The type  of constituent  materials used for making the concrete.
  2. Mixing ratio of the materials; the amount of cement being a very important factor.

Concrete grades are usually designated with the letter C followed by its typical strength at 28 days.

For instance, a Concrete grade mix of C7.5 means that it has a strength of 7.5 N/mm2 after 28days. This type of concrete is only useful for light weight loading.

On the other hand a concrete grade mix of 25N/mm2 is a heavy duty concrete containing dense aggregate.  This grade of concrete is what is acceptable for reinforced concrete works. The mix for this grade is 1 part  of cement to 2 parts of fine aggregates (sand) to 4 parts of coarse (stone) aggregates. Mix ratio 1:2:4

Cement

50kg bag of Cement

Cement is the binding agent that binds sand or sand and rock to form a  very strong concrete mass within a few days. Without cement, there is no concrete. Without cement there is no mortar.

Concrete has made it possible to build structures never before possible. Without cement to make the concrete, it would have been impossible.

Small graded rock particles, sand, cement and water are mixed together in certain proportions to make concrete. The water interacts with cement to bind the mixture into a solid mass within a few days.

There are different types of cement including;

Ordinary Portland cement,

Rapid hardening cement,

Low heat cement,

White ordinary portland cement… and so on. The common thing all these types of cement do is to Bind together when water is added.

The ordinary Portland cement is the most produced type of cement. It is suitable for all kinds of concrete and mortar works.

Cement is usually supplied in 50kg and 25kg bags. It has a volume of 0.033 cubic meter and density of 1440kg per cubic meter. 

Hollow Sandcrete Blocks

Hollow sandcrete blocks are the common units for wall construction in West Africa and many parts of the world. The blocks are designed hollow to make them easier to carry. The hollowness of the blocks also enable easier placement of conduit pipes and other accessories inside the wall.

Hollow sandcrete Block

Sandcrete hollow blocks are made of cement, sand and water in controlled proportions. 

A block making machine moulds the block into shape, then compresses and compacts it before it is left to dry in the sun.

Sandcrete blocks can be used for the construction of load or non load bearing walls. They also have very good fire resistance properties. 

The blocks are produced in various sizes. The 225mm( thick) by 225mm (height) by 450mm ( length) is used for external wall construction, while the 150mm(thick) by 225mm ( height) by 450mm ( length) is used for internal wall partitions.