Roof Beam - Concrete Or Steel

[watchthewaves 0]

As above. Roof will be clay tiles. "Normal" pitched design, nothing fanciful, no curves. Appreciate it if the experienced people could chime in on the relative pros and cons on using concrete or steel to support the roof.

Is there any concern of the steel rusting?

Thanks.

[leechaorui 2]

As above. Roof will be clay tiles. "Normal" pitched design, nothing fanciful, no curves. Appreciate it if the experienced people could chime in on the relative pros and cons on using concrete or steel to support the roof.

Is there any concern of the steel rusting?

Thanks.

I think the problem with using steel is the concern for rust. After some time, you will find that there are lots of tiny rust dropplets dropping down from the roof.

For concrete beams, it is generally very strong. One issue is its weight. This means that when you build the structure of your house, you have to take into account the load on the building. Concrete can also be porious and this could present problem of water leakage. Hence, you will need to make sure that sealant is applied on it and also preferably use high quality concrete that is water-proofed. For the rest of the supporting roof structures, you can use treated mature hard wood. Below the ground, make sure you have anti-termite treatment done.

[pantieileen 2]

.

Edited October 12, 2011 by pantieileen

[indira 0]

The flat roof building is originally from sub-tropical country, for tropical country like Singapore, roof with angle are preferred because of the high rainfall.

There are many wood materials that dont need to be treated with anti termite because it is naturally anti termite, such as bamboo. The strength for tension, shear and compression are already tested by some projects such as 33 m long bridges. I think it is worth to be considered.

Cheers,

[yoongf 11]

At which stage of construction are u at, becuase once the structural plans are approved, this is not a changeable item.

Clay roof tiles are normally supported by wooden purlins.

Concrete or steel is not a usual material, unless u are referring to the beams holding up the wooden purlins?

Ideally, beams should be concrete, but if the span is long, then the thickness will be an issue, and steel is preferred.

Steel can be galvanised to reduce corosion issues. The area is hot and humid, so painted is not ideal.

[watchthewaves 0]

Yes, the beams and support for the wooden purlins and rafters. Galvanised? I was given to understand that in general, galvanised steel would be used for structures that are exposed to the elements (eg, outdoor or external parts), and that for covered structures, a coat of paint is sufficient. I suppose if one were to use galvanised steel, it would be over-speccing just to be kiasu?

[leechaorui 2]

Yes, the beams and support for the wooden purlins and rafters. Galvanised? I was given to understand that in general, galvanised steel would be used for structures that are exposed to the elements (eg, outdoor or external parts), and that for covered structures, a coat of paint is sufficient. I suppose if one were to use galvanised steel, it would be over-speccing just to be kiasu?

Useful to opt for a build to last concept in erection of new structure. A very strong foundation that factor in the weight of a solid water-proof concrete beams and structure for the roof that is good to last conservatively 200 years and beyond is definitely a plus. You can then add treated outdoor weather proof thick hard wooded purlins and rafters to support large pieces of German roof tiles with high quality insultation that comes with 50 years manufacturer's warranty. This is the specifications that I used. In fact, the engineers felt that three strong concrete beams would be more than sufficient but I told him that in future, I may want to shift a large water tank and water pump above the 45 degree slope roof, so he added in another huge beam. Actually, my current water pump and water tank is already housed nicely between my first and second storey. Nonetheless, the space above the sloping roof may have some very heavy potential usage that I have not considered now. Hence, design it to take a weight of more than 6 tons. The improved structure is transparent to the homeowner as the beams are well hidden from sight and doesn't take up useable space.

Was told that steel tend to rust over time and usually only build to take the weight of roof tiles. Although the dropping rust from steel beams can be contained by the false ceiling and some of these rust dropplets can fall through the downlights over time, people generally don't feel that it is much of a concern as long as they don't need to remove the false ceiling to do maintenance work on air-con pipes, water pipes, electrical wiring, fans installation brackets, storage water heater tank, telephone wires, internet broadband CAT6 cables, etc... The space between the concrete ceiling and false ceiling can be quite humid, causing steel to rust. If budget permits, I think is better to install concrete beams for the key roof structure.

Edited June 7, 2011 by leechaorui