Tubular Steel Monitor Roof truss | Large Span Constructions

Steel Trusses

The trusses are structural members and comprise of one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes. The triangular members arranged in series and supported on the walls.

Major use of steel trusses is being done in the construction of large span structures such as industries, factories, Auditoriums, Cinema Theatres, Shopping Malls, Concert Halls etc.

Trussed Bridge
Trussed Bridge

But the use of steel trusses is not limited to various types only. Major use of trusses is also seen in the construction of bridges.

Roof coverings used over Steel trusses

RCC roof can be used over the trussed construction but usually to keep the roof lightweight, asbestos sheets are used as roof covering.

Plastics sheets are also used as roof covering.

In this article, we are going to discuss in detail about the Tubular Monitor Roof Truss.

“Tubular Steel Roof Truss” is also largely used for large span constructions but the lighting arrangements in these kind of roof is different from that of “Tubular Monitor Roof Truss”

Tubular Monitor Roof Truss

  • This is a flat roof with raised portions called monitors, used to admit light.
  • This type of roofing gives a more uniform level of daylighting than North light system.
  • Main lattice girders span the shorter distance.

Tubular Steel Monitor Roof Truss
Tubular Steel Monitor Roof Truss

  • Lattice girders connect between the main columns and intermediately to the main girder.
  • The depth of the girder is about 1/8th or 1/12th of the span.
  • The monitor frame tubes are welded to the monitor girder, these are roofed on the top surface and have patent glazing to the tiles.
  • Curved socket plates are welded to the column in two halves, the column arrives on the side with the bottom sockets in position and the top ones are site welded after positioning of the girder.

Details of Tubular Steel Monitor Roof Truss
Details of Tubular Steel Monitor Roof Truss
  • A detail at D is at the foot of the glazed opening light. A metal enclosure plate is screwed to the roof decking and to the Purlin angle.
  • After roofing, felt is laid, the roof is sealed by a lead flashing.
  • The glazing bars are screwed to angle frame to which the opening gear is attached.
  • Detail at G is shown at F is a junction of the monitor roof and the top of the glazed opening light.
  • The angle purlin is bolted to a tee cleat welded to the top tube of the monitor. Welding is done instead of bolting.

Uses of Tubular Steel Monitor Roof Truss

It is used in large span constructions such as:

  • Factories
  • Large Community Meeting Halls
  • Industrial Work Zone
  • Shopping Malls

It is seen that these trusses are used in large span structures that require large amount of natural lighting for their efficient functioning.

12 thoughts on “Tubular Steel Monitor Roof truss | Large Span Constructions”

    • Metal roofs are quite preferable for the countries in the North mostly because of its snow shedding quality. Painted metal roofs are usually snow-shedding. Snow can usually collect when it is fresh and lighter weight. As soon as the ambient temperature rises a couple degrees, the snow usually just slides off. For this reason metal roofing is ideal for homes in northern or mountain regions. It also has many other advantages over ceramic not to forget its energy efficiency.

      Cheers 🙂

      • Hi, I am planning on requesting a 12m suspended porte cochere at my house and wonder if this is even doable. I have seen it elsewhere in more expensive commercial buildings. Is this viable for a home? The reason why I cannot put a pillar below the porte cochere is because there is a carousel which ends a driveaway, and in the middle of that carousel is a fountaing and a round pond. Any ideas?

    • You should go for Steel Girders and not Plastic Girders. Steel has higher bending modulus and can take up lot of stress and load. Sports Hall is a large span structure… Steel Girders are an excellent option to span large span structures.
      You have to go through Code books for Steel Structures and also refer steel tables….

      • Hi Benzul

        you seem like someone who knows a lot about roofs.

        I have a balcony around 75 sq ft which I would like to cover and take into my bedroom.

        The balcony is open to sky and it rains heavy for 4 months of the year in mumbai.

        I am planning to put asbestos cement sheets or any other suitable material. I am told that asbestos is not good for health.

        pl advise.

        Prakash Mahtani

        • Hello Mr Prakash,

          These days, we can get many stylish Acrylic roofing sheets and Coloured Aluminium sheets which can be used. Asbestos cement sheets might be cheaper, but wouldn’t prefer them…


  1. This reason metal roofing is ideal for homes in northern or mountain regions. It also has many other advantages over ceramic not to forget its energy efficiency. Thank you.

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