Kumar IronUpdated
In this guide
Which section for which part
- Round bar: window grill bars, railing balusters, gate infill, anchor pins.
- Square bar: grill bars where a firmer, sharper look is wanted, and for gate infill where the bar is welded at corners.
- Flat bar: frames and borders, scrolls and decorative work, base plates, and straps.
- MS pipe or hollow section: the main frame of a gate, covered in our pipe sizes guide.
Common sizes for household work
| Job | Section | Typical size |
|---|---|---|
| Window grill vertical bars | Round or square | 10 to 12 mm |
| Window grill frame | Flat | 25 x 5 mm or 32 x 6 mm |
| Main gate infill | Square | 12 mm |
| Railing balusters | Round or square | 12 mm |
| Balcony and staircase handrail frame | Flat or pipe | 40 x 6 mm, or 32 to 40 mm pipe |
Sizes depend on opening width, security need and design. Confirm with your fabricator.
Weight formulas
Steel weighs about 7850 kg per m³. These short forms give kilograms per metre.
- Round bar: D² / 162, where D is the diameter in mm. A 12 mm round bar is 0.888 kg per metre.
- Square bar: D² / 127.4, where D is the side in mm. A 12 mm square bar is 1.13 kg per metre.
- Flat bar: width x thickness x 0.00785, in mm. A 25 x 5 mm flat is 0.98 kg per metre.
The flat, round and plate weight chart on this site has the full table, so you do not have to calculate by hand.
Estimating a window grill, worked example
A window of 1200 x 1200 mm with 12 mm square bars at 100 mm spacing needs about 11 verticals, each 1200 mm plus 50 mm embedded at each end, so 1.3 m. Total bar is 14.3 m, weight 14.3 x 1.13 = 16.2 kg. The frame is 4 x 1.2 m = 4.8 m of 25 x 5 flat, weight 4.7 kg. Add 5 to 8 percent for cutting waste, and the job is about 22 kg.
Painting and rust
Plain MS rusts. Apply a red oxide primer before the final paint, and seal the cut ends. For grills in humid or coastal conditions, galvanised sections last longer.
Frequently asked questions
- Can I use TMT bars for a grill?
- It is not what they are for. TMT bars have ribs and are made for reinforcing concrete. Use plain MS round or square bar for gates and grills.
- How much does a 12 mm square bar weigh per metre?
- About 1.13 kg per metre, using the D² / 127.4 formula.
- Do you sell these sizes?
- Yes. We stock MS round, square and flat bars in many sizes. Send us the size and length on WhatsApp for today's rate.