SHS Calculator UK 2026 | Square Hollow Section Properties, Weight & Cost Estimator

SHS Calculator UK

Square Hollow Section Properties, Weight, Deflection, Moment Capacity & Cost Estimator – 2026

SHS Section Properties & Cost Calculator 2026

Select an SHS size to retrieve full section properties (cross-section area, second moment of area, section modulus, radius of gyration, torsional properties), then enter member length, loading, and supply details to calculate total weight, estimated mid-span deflection, indicative moment capacity, and supply cost. SHS data is taken from BS EN 10210-2:2019 (hot-finished) and BS EN 10219-2:2019 (cold-formed). All structural design must be carried out by a chartered structural engineer to Eurocode 3 (BS EN 1993).

SHS Manufacturing Process

SHS Size (outside dimension × wall thickness)

Steel Grade

Member Length (metres)

Number of Members

Primary Role / Use

Loading Condition (for deflection & moment check)

Total Applied Load (kN) – excl. self-weight

Support Condition

Supply Type

Surface Finish / Protection

UK Region

SHS Results 2026:

Section Properties (BS EN 10210 / BS EN 10219)

Designation:

Mass: kg/m | Process: | Grade:

Outside Dimension (b × h): mm × mm

Wall Thickness (t): mm | Corner radius (r_o): mm

Cross-Section Area (A): cm²

Gross cross-sectional area; no holes deducted

Second Moment of Area (I): cm⁴

Equal in both axes (square section); governs bending stiffness and deflection

Elastic Section Modulus (W_el): cm³

Governs bending resistance at onset of yielding

Plastic Section Modulus (W_pl): cm³

Governs full plastic moment capacity (Class 1 & 2 sections)

Radius of Gyration (i): cm

Equal in both axes (square section); used for column buckling and LTB calculations

Torsional Constant (I_T): cm⁴

Closed section: I_T ≈ 2 × A_m² × t / perimeter; far superior to open sections of equivalent mass

Section Perimeter (heated, H_p): mm

4 × b; used for fire protection design (H_p/A section factor)

H_p/A Section Factor: m⁻¹

Section factor governs fire protection requirement; lower is better (more thermally massive)

Member Calculations

Self-Weight: kN total ( kN/m)

For × m members at kg/m

Total Weight (net): kg ( tonnes)

Bare section weight; no connections included

Total Weight (incl. 10% connections): kg ( tonnes)

Gusset plates, end plates, cleats, and weld consumables typically add 8–15%

Design Moment Resistance (M_c,Rd): kNm

= W_pl × f_y / γ_M0; Class 1/2 section check required; SHS rarely subject to LTB for minor-axis bending

Applied Moment (M_Ed, indicative): kNm

Based on entered load, span, and support condition; preliminary sizing only

Moment Utilisation:

Euler Buckling Load (N_cr): kN

Critical elastic buckling load for pin-ended column (N_cr = π²EI/L²); actual design resistance is lower — structural engineer must check to EC3 Clause 6.3

Estimated Deflection (mid-span): mm

Elastic; applied load only; E = 210,000 N/mm²;

Span / Deflection Ratio:

UK typical limit: span/360 for floor beams (imposed load); span/200 for total load

Cost Estimate

Steel Supply Cost (excl. VAT): £

; mid-range 2026 UK stockholder price per tonne for S355 SHS

Finish / Protection Cost: £

Total Material Cost (excl. VAT): £

Steel + finish; excl. erection, connections, and design

Total (incl. 20% VAT): £

Standard rate VAT; zero-rated for new residential build in some circumstances

Typical Low–High Range: £ – £

Steel is commodity-priced; obtain live quotes before budgeting

Embodied Carbon: kg CO₂e

~1,550 kg CO₂e/tonne for UK EAF structural steel (incl. 10% connections allowance)

Square Hollow Section (SHS) – UK Guide 2026

A Square Hollow Section (SHS) is a structural steel tube with a square cross-section — equal outside dimensions in both the horizontal and vertical planes. SHS is one of the three principal hollow section types used in UK construction (alongside Rectangular Hollow Section, RHS, and Circular Hollow Section, CHS), and is manufactured to either BS EN 10210-2:2019 (hot-finished structural hollow sections) or BS EN 10219-2:2019 (cold-formed structural hollow sections). In the UK in 2026, SHS is most commonly specified in grade S355J2H (hot-finished) or S355J2H (cold-formed) — the J2H suffix indicating a Charpy impact requirement and that the section is a hollow section product.

SHS sections are designated by their outside dimension and wall thickness — for example, 150×150×8 SHS denotes a section with 150mm outside dimensions on all four sides and an 8mm wall thickness. The symmetrical square geometry gives SHS equal second moment of area, section modulus, and radius of gyration in both principal axes — making it ideal for columns where equal buckling resistance is required in all directions, and for members subject to biaxial bending. This equal stiffness in all directions is the primary structural advantage of SHS over open sections (UB, UC, IPE) as a column, and over RHS where there is a preferred bending axis.

The closed hollow section geometry of SHS provides exceptional torsional stiffness — the torsional constant I_T of a hollow section is orders of magnitude greater than that of an open section of equivalent mass, because the enclosed cell area resists torque through Bredt-Batho flow rather than the much less efficient St Venant torsion that dominates in open sections. This makes SHS particularly effective in applications where torsion is present — crane runway beams, space frames, and members carrying eccentric loads.

Hot-Finished vs Cold-Formed SHS

UK SHS is available in two manufacturing routes, each with different structural properties and cost implications:

Hot-Finished SHS (BS EN 10210): Produced by hot-forming a seamless or welded tube and finishing above the re-crystallisation temperature of steel. This process produces uniform wall thickness, smooth internal and external corners with a consistent radius, and relieves residual stresses — resulting in sections with properties that more closely approximate ideal theoretical values. Hot-finished sections have higher torsional constants and are specified for structural applications where the section properties must be relied upon fully. Also known as structural hollow sections (SHS). Typically more expensive than equivalent cold-formed sections.
Cold-Formed SHS (BS EN 10219): Produced by cold-forming a flat plate or strip into a tube at ambient temperature, then welding the seam. The cold-forming process introduces residual stresses and work-hardens the corners — which has a modest negative effect on the effective yield strength at corners, reducing the torsional constant slightly. Cold-formed sections are available in a wider range of sizes and thicknesses than hot-finished, are generally cheaper, and are adequate for most non-critical structural applications. Their properties are slightly less favourable than hot-finished for the same nominal dimensions.

Common SHS Applications in UK Construction 2026

Structural columns: The primary use of SHS in UK construction — the equal dimensions and biaxial symmetry make SHS ideal for columns resisting load in any direction. 100×100 to 300×300 SHS in S355 covers the majority of UK residential and commercial column applications.
Space frames and trusses: SHS nodes in space frames allow welded connections in any direction. The torsional stiffness and equal-axis properties of SHS make it well-suited to three-dimensional frame systems.
Architectural steelwork: The clean, flat faces of SHS present a modern aesthetic popular in exposed structural steelwork, balustrades, balcony frames, and feature columns in commercial and residential buildings.
Gate posts and fencing: 50×50 to 100×100 SHS (typically 3–5mm wall) is the standard specification for welded steel gate posts, fence posts, and barrier structures in UK domestic and commercial applications.
Handrails and balustrades: Smaller SHS (40×40 to 60×60) are used for handrail infill panels and balustrade frames where the flat face is preferred over CHS for welded connections and a contemporary appearance.
Crane runway beams: SHS is used for runway beam bottom flanges and runway support columns where torsional stiffness is important to resist lateral loads from crane operation.

SHS Section Properties – UK Reference Table 2026

Properties for hot-finished SHS to BS EN 10210-2:2019. I and W_pl are equal for both axes (square section). M_c,Rd values assume Class 1 section with γ_M0 = 1.00. Highlighted rows are commonly stocked sizes. Always verify section class at actual grade before using plastic section modulus.

Size (mm)	t (mm)	kg/m	A (cm²)	I (cm⁴)	W_el (cm³)	W_pl (cm³)	i (cm)	I_T (cm⁴)	H_p/A (m⁻¹)	M_c,Rd S275 (kNm)	M_c,Rd S355 (kNm)
40×40	3	3.45	4.39	8.04	4.02	4.97	1.35	12.9	363	1.37	1.76
40×40	4	4.39	5.59	9.50	4.75	5.98	1.30	15.1	285	1.64	2.12
50×50	3	4.35	5.54	15.9	6.37	7.84	1.70	25.5	289	2.16	2.78
50×50	4	5.72	7.28	19.9	7.97	9.90	1.65	31.5	220	2.72	3.52
50×50	5	6.97	8.88	23.3	9.32	11.7	1.62	36.7	180	3.22	4.16
60×60	3	5.27	6.71	28.2	9.41	11.5	2.05	44.9	239	3.16	4.08
60×60	4	6.97	8.88	36.0	12.0	14.8	2.01	57.1	181	4.07	5.25
60×60	5	8.54	10.9	42.6	14.2	17.6	1.98	67.5	147	4.84	6.25
70×70	4	8.23	10.5	59.5	17.0	20.9	2.38	94.1	152	5.75	7.42
70×70	5	10.1	12.9	71.1	20.3	25.2	2.35	112	124	6.93	8.95
80×80	4	9.50	12.1	90.9	22.7	27.8	2.74	143	132	7.65	9.87
80×80	5	11.7	14.9	110	27.4	33.8	2.72	172	107	9.30	12.0
80×80	6	13.8	17.6	125	31.3	39.0	2.67	196	91	10.7	13.8
100×100	5	14.8	18.9	222	44.4	54.9	3.43	350	85	15.1	19.5
100×100	6	17.5	22.3	256	51.2	63.8	3.39	401	72	17.5	22.7
100×100	8	22.9	29.2	318	63.5	80.4	3.30	494	55	22.1	28.5
100×100	10	27.9	35.5	368	73.7	94.4	3.22	567	45	26.0	33.5
120×120	5	17.8	22.7	388	64.7	79.7	4.14	613	71	21.9	28.3
120×120	6	21.2	27.0	453	75.5	93.7	4.10	713	59	25.8	33.3
120×120	8	27.8	35.4	573	95.5	120	4.02	894	45	33.0	42.6
120×120	10	34.0	43.3	674	112	142	3.95	1040	37	39.1	50.4
150×150	6	26.8	34.2	924	123	152	5.19	1454	47	41.8	54.0
150×150	8	35.4	45.1	1183	158	197	5.12	1848	36	54.2	69.9
150×150	10	43.6	55.5	1403	187	235	5.03	2170	29	64.6	83.4
150×150	12	51.5	65.6	1594	213	269	4.93	2450	24	74.0	95.5
160×160	6	28.7	36.6	1139	142	176	5.58	1791	44	48.4	62.5
160×160	8	37.9	48.3	1459	182	228	5.50	2281	33	62.7	80.9
160×160	10	46.7	59.5	1732	217	274	5.40	2683	27	75.4	97.3
200×200	8	47.7	60.8	2966	297	369	6.99	4662	26	102	131
200×200	10	58.8	74.9	3579	358	449	6.91	5584	21	123	159
200×200	12	69.6	88.7	4127	413	521	6.82	6404	18	143	185
200×200	16	90.3	115	5057	506	646	6.63	7776	14	178	229
250×250	10	73.9	94.1	7068	565	703	8.66	11120	17	193	250
250×250	12	87.7	112	8216	657	821	8.60	12880	14	226	292
250×250	16	114	145	10270	822	1035	8.41	15990	11	285	368
300×300	10	89.6	114	12380	825	1022	10.4	19560	14	281	363
300×300	12	106	135	14500	967	1203	10.4	22820	12	331	427
300×300	16	139	177	18340	1223	1535	10.2	28620	9	422	545
350×350	10	105	134	19840	1134	1401	12.2	31400	12	385	497
350×350	12	124	158	23350	1334	1655	12.2	36870	10	455	588
350×350	16	163	207	29790	1702	2127	12.0	46780	8	585	755
400×400	10	121	154	30230	1511	1862	14.0	47870	10	512	661
400×400	12	143	182	35660	1783	2205	14.0	56370	9	607	783
400×400	16	188	239	45840	2292	2853	13.8	72120	7	785	1013

SHS Cost Guide UK 2026

SHS Size Range	Supply Cost per Tonne (2026)	Cut to Length Premium	Fabricated (primed, drilled)	Hot-Dip Galvanised	Notes
Light SHS (40–80mm, t ≤ 5mm)	£900–£1,100/tonne	+£60–£100/tonne	+£450–£750/tonne	+£430–£650/tonne	Architectural and fencing sizes; small quantity premiums common
Medium SHS (100–200mm)	£860–£1,060/tonne	+£50–£80/tonne	+£400–£700/tonne	+£400–£600/tonne	Main structural range; best availability and pricing
Heavy SHS (250–400mm)	£840–£1,020/tonne	+£60–£100/tonne	+£380–£680/tonne	+£400–£600/tonne	Large columns and heavy frames; check availability; may require order from mill
Hot-finished premium over cold-formed	+£30–£80/tonne	—	—	—	Hot-finished offers better section properties and is preferred for structural use
S355 premium over S275	+£20–£50/tonne	—	—	—	S355 is now the default UK grade for structural SHS; S275 rarely specified

SHS resources UK 2026: Steel Construction Info – Section Properties | Tata Steel – Celsius® 355 Hot-Finished SHS | BCSA – Find a Fabricator | IStructE – Find a Structural Engineer | BSI – BS EN 10210 / BS EN 10219

Additional Costs for SHS Projects UK 2026

Item / Extra	Typical Cost Range (2026)	Notes
Delivery (loose SHS, per load)	£120–£250 per load	Standard stock lengths 6m or 8m; confirm lorry access before ordering
Mitring / end preparation	£15–£50 per cut end	Mitred ends for frame joints; square-cut ends for column base plates
End plate welding (base plate / cap plate)	£40–£120 per plate welded	Column base plates and beam end plates; design by structural engineer
Column base plate supply and fabrication	£60–£200 per base plate	Plate thickness typically 15–25mm; weld fillet or full penetration as specified
Anchor bolts (per column base)	£20–£120 per base group	Cast-in or resin-anchored; M20–M30 typically; design to Eurocode 3 Part 1-8
Mobile crane hire (erection)	£650–£1,500/day + driver	For columns over approximately 150kg (single-piece lift); size depends on load and radius
Steel fixer / welder (erection labour)	£350–£600/tonne erected	Includes crane signal, alignment, bolting or tacking; complex welded connections at higher end
Concrete in-fill (to hollow section)	£8–£20/m length filled	Concrete-filled SHS columns have significantly enhanced axial and fire resistance; pump via holes in end plate
Intumescent fire protection (60 min)	£25–£75/m² section perimeter	Required dry film thickness depends on H_p/A section factor and fire rating; shop applied preferred
Box section fire protection (board or spray)	£30–£80/m length	Alternative to intumescent for columns; board or spray systems; encases section in fire-resistant material
Structural engineer design fee	£300–£2,000 depending on project	Essential for all structural SHS applications; Eurocode 3 column design including buckling check
BCSA CE marking / EN 1090 compliance	Included in fabricator overhead	Required for structural steelwork placed on the market in UK; confirm fabricator holds appropriate execution class

Essential Facts About SHS – UK 2026

Equal Properties in All Directions

SHS has equal second moment of area, section modulus, and radius of gyration in both principal axes. This makes it uniquely suited to columns carrying load in any direction and members subject to biaxial bending. Unlike UBs and UCs (which have very different properties in major and minor axes), SHS offers no preferred bending or buckling axis — a structural advantage for columns and frame members where loading direction is variable or unknown.

Superior Torsional Stiffness

The closed box section of SHS provides torsional stiffness many times greater than open sections of equivalent mass. The torsional constant I_T for a 150×150×8 SHS is approximately 1,848 cm⁴ — compare this to an equivalent-mass 305×127×48 UB where I_T is only 29.5 cm⁴. This gives SHS exceptional resistance to twisting under eccentric loads and makes it the preferred section for members where torsion is a primary design consideration.

S355 Is the Standard UK Grade for SHS

Unlike Universal Beams where S275 remains common, S355 is the standard and most widely specified grade for structural SHS in UK construction in 2026 — particularly for hot-finished sections. The full designation is typically S355J2H (hot-finished) or S355J0H (cold-formed) — where J2 denotes 27 Joule Charpy impact energy at -20°C and H denotes a hollow section. Always confirm the full designation (including impact class) when ordering structural SHS.

Section Classification

Eurocode 3 section classification for SHS depends on the width-to-thickness ratio b/t. For S355 hot-finished SHS, the limiting b/t ratio for Class 1 is 33.0 (= 38ε, where ε = √(235/355) = 0.814). Most standard structural SHS in S355 with wall thickness ≥ 5mm are Class 1 — allowing use of the plastic section modulus W_pl in bending design. Very thin-walled SHS (t = 3mm, large dimension) may be Class 3 or 4 — always check section class in the SCI Blue Book or EN 10210 tables before using W_pl.

No Lateral-Torsional Buckling for Major-Axis Bending

Due to its closed section geometry and high torsional stiffness, SHS is not susceptible to Lateral-Torsional Buckling (LTB) in bending about its major axis (χ_LT = 1.0 per Eurocode 3 Clause 6.3.2.2 for square hollow sections). This is a significant advantage over UBs, where LTB can dramatically reduce the effective moment capacity for unrestrained spans. SHS beams can be designed using the full plastic moment resistance M_c,Rd without LTB reduction in most practical cases.

Stock Lengths 6m and 8m

UK steel stockholders typically stock SHS in 6m and 8m lengths for standard structural sizes. Some lighter architectural sizes are available in 3m and 4m lengths. Larger or less common sizes may need to be cut from mill lengths (typically 12m) at the stockholder, adding a cutting charge. Always confirm stock availability and lead times for your required size before committing to a programme — some heavy SHS sections (350×350 and above) may not be stocked locally and require mill order with 6–10 week lead time.

Concrete-Filled SHS Columns

Filling an SHS column with concrete (concrete-filled hollow section, CFHS) significantly enhances its axial load capacity and fire resistance. The concrete prevents local buckling of the steel walls, and the steel confines the concrete — both materials working together more efficiently than either alone. CFHS columns also provide substantial inherent fire resistance (up to 60–90 minutes without additional fire protection for lightly loaded columns), potentially eliminating the need for expensive intumescent coatings. Design to BS EN 1994-1-2 (composite column design).

Fire Protection and Hp/A

The fire protection requirement for SHS depends on the section factor H_p/A — the heated perimeter (4 × b for SHS) divided by the cross-sectional area. A lower H_p/A means the section is more thermally massive — it heats up more slowly and requires less intumescent protection. For a 200×200×10 SHS, H_p/A ≈ 213 m⁻¹, making it easier and cheaper to fire-protect than a lighter, thinner-walled section. Compact SHS sections have significantly lower H_p/A than equivalent-mass open sections, which is a fire protection advantage.

Welded Connections – Design Considerations

SHS connections involve welding directly to the hollow section wall, which can be challenging when the connecting member is perpendicular to the SHS face. Direct welded T, Y, and K joints in hollow sections must be designed to BS EN 1993-1-8 Chapter 7 (joints in hollow sections), checking: chord face failure; chord side wall failure; chord shear; punching shear; and brace failure. The wall thickness of the chord SHS must be sufficient to carry the local stresses — joints to thin-walled SHS may require stiffening.

Closed Ends for External Use

When SHS is used externally (gate posts, fencing, balustrades), the open ends must be sealed with welded cap plates or proprietary end caps to prevent moisture ingress into the hollow interior. Water entering an unsealed SHS will accelerate internal corrosion from the inside out — which is invisible until the section is structurally compromised. All external SHS must also be adequately protected with hot-dip galvanising or a quality paint system, with particular attention to weld zones and cut ends where the protective coating is disrupted.

Weight Comparison – SHS vs UC for Columns

For a typical 3m-high domestic column carrying moderate axial load, a 150×150×8 SHS (35.4 kg/m) and a 203×203×52 UC (52 kg/m) may offer comparable column capacity — but the SHS is approximately 32% lighter. The SHS also has equal buckling resistance in both directions without the disparity between major and minor axis stiffness that affects UC design. However, UCs are generally cheaper per tonne than SHS and have a larger flange face for beam connections. The choice depends on the specific loading condition and connection details.

Embodied Carbon

UK-produced SHS from Electric Arc Furnace (EAF) steelmaking carries approximately 1,400–1,600 kg CO₂e/tonne — equivalent to UBs and UCs from the same route. The additional energy consumed in forming the hollow section (compared to rolling a flat section) is modest. Specifying S355 to reduce section weight and using efficient structural design (avoiding over-specification) are the primary strategies for minimising SHS embodied carbon. EPDs are available from major UK hollow section manufacturers on request.

Frequently Asked Questions – SHS UK 2026

What is SHS steel and what is it used for?

SHS (Square Hollow Section) is a structural steel tube with a square cross-section — equal outside dimensions on all four sides. It is manufactured to BS EN 10210 (hot-finished) or BS EN 10219 (cold-formed) and is most commonly supplied in grade S355. SHS is used primarily as structural columns (where its equal biaxial stiffness is the key advantage), in space frames and trusses, for architectural steelwork and feature columns, as gate posts and fence posts, in handrails and balustrades, and in any structural application where high torsional stiffness and a clean square profile are required. Its equal-axis properties make it ideal wherever the direction of loading is variable or the column must resist loads in any direction.

What is the difference between hot-finished and cold-formed SHS?

Hot-finished SHS (BS EN 10210) is produced by hot-forming above the steel's recrystallisation temperature, producing uniform wall thickness, smooth corners with consistent radius, and low residual stresses. The result is sections with properties closely matching their theoretical values — the preferred specification for structural use. Cold-formed SHS (BS EN 10219) is produced by cold-forming flat strip into a tube and welding the seam at ambient temperature. This is cheaper but introduces residual stresses and work-hardened corners that slightly reduce effective section properties — particularly torsional constants. For structural applications, always specify hot-finished unless the engineer has confirmed cold-formed is acceptable. The difference in cost is typically £30–£80/tonne.

How do I read an SHS designation?

An SHS designation such as 150×150×8 SHS describes the section by three numbers: the first two (150×150) are the outside dimensions in millimetres — for SHS, both are equal (making it square). The third number (8) is the wall thickness in millimetres. The inside dimension is therefore 150 - (2 × 8) = 134mm. The section is typically referred to as "150 by 150 by 8" in the trade. Unlike UBs (where the mass per metre is the third designation number), SHS uses the wall thickness — so always specify the full three-number designation when ordering to avoid ambiguity.

Can SHS be used as a column without a structural engineer?

No — any SHS used as a structural column must be designed by a chartered structural engineer to Eurocode 3 (BS EN 1993-1-1). Column design involves checking: the cross-section resistance under combined axial load and bending; flexural buckling about both axes (using the column buckling curves in Eurocode 3 Clause 6.3.1); and the connection design at base plate and beam connections. Even seemingly simple column arrangements involve these checks, which require knowledge of the applied loads, effective lengths, section classification, and member imperfection factors. For domestic and commercial projects subject to Building Regulations, engineer calculations and Building Control approval are required.

Does SHS suffer from lateral-torsional buckling?

No — SHS (and RHS) are not susceptible to lateral-torsional buckling (LTB) when bent about either principal axis, because the closed hollow section geometry provides very high torsional stiffness. Eurocode 3 explicitly permits χ_LT = 1.0 (no LTB reduction) for square hollow sections, meaning the full plastic moment resistance M_c,Rd can be used in bending design without checking LTB. This is a significant advantage over UBs and IPE sections, where LTB can substantially reduce the effective moment resistance for unrestrained spans and must always be checked. For SHS beams, only cross-section resistance and deflection need to be verified for most practical applications.

What size SHS do I need for a gate post?

For a typical domestic garden gate or driveway gate, common SHS gate post sizes are: 60×60×4 SHS or 60×60×5 SHS for lightweight pedestrian gates up to 1m wide; 80×80×4 SHS or 80×80×5 SHS for standard garden gates up to 1.5m wide; 100×100×5 SHS or 100×100×6 SHS for heavier driveway gates up to 2.5m wide; and 120×120×6 SHS or larger for electric gates, very wide (3m+) or heavy gates, and gates in exposed or high-security applications. These are indicative guides — for gates over 2m wide, electric gates, or commercial applications, the post size and foundation depth should be checked by a structural engineer or specialist gate installer. Always seal the post ends with cap plates to prevent water ingress.

How much does SHS cost in the UK in 2026?

Standard structural SHS in S355 costs approximately £860–£1,060 per tonne for medium sizes (100–200mm) in stock lengths in South East England in 2026, plus delivery of £120–£250 per load. In practical terms for common sizes: a 100×100×6 SHS in 3m length costs approximately £15–£20; a 150×150×8 SHS in 6m length costs approximately £115–£145; a 200×200×10 SHS in 6m length costs approximately £195–£245. Fabricated sections (shot-blasted, mitred, drilled, primed) add £400–£700/tonne over stock price. Hot-dip galvanised SHS adds £400–£600/tonne. Steel prices are commodity-driven — always obtain current quotes before committing to a project budget.

What is the Hp/A section factor and why does it matter for SHS?

The section factor H_p/A (also written A_m/V in Eurocode 3 Part 1-2) is the ratio of the heated perimeter of a steel cross-section to its cross-sectional area, expressed in m⁻¹. It governs how quickly a steel section heats up in a fire — a high H_p/A means the section has a large surface area relative to its mass, and heats up quickly, requiring more fire protection. For SHS, H_p/A = 4b/A (in consistent units), where b is the outside dimension. Compact, thick-walled SHS have low H_p/A values — for example, a 200×200×16 SHS has H_p/A of approximately 140 m⁻¹ — making them inherently more fire-resistant and cheaper to protect than lightweight open sections with equivalent area.

Can SHS be welded and drilled for connections?

Yes — SHS can be welded and drilled for structural connections, but both operations require care. Welding to the SHS face creates a fillet or butt weld connection — the weld design must comply with Eurocode 3 Part 1-8, and the SHS wall must be thick enough to carry the local stresses without chord face failure. Thin-walled SHS (t ≤ 4mm) should be avoided for highly loaded welded connections. Drilling for bolted connections is straightforward but requires that both the bolt head or nut and the installation tool can fit inside the hollow section — or that a captive (blind) bolt or flow-drill connection system is used where internal access is impossible. Always specify the connection details to your structural engineer before ordering material.

How do I find a reliable SHS supplier in the UK?

For standard SHS in stock lengths, major UK steel stockholders include Rainham Steel, Barrett Steel, Metals4U, AJN Steelstock, and numerous regional and national tube and section suppliers. For fabricated SHS (cut, mitred, welded, and primed to drawing), use a BCSA member fabricator with appropriate BS EN 1090 CE marking for your execution class (EC1 for most domestic/light commercial; EC2 for most structural work). For architectural SHS (galvanised, powder-coated, or specialist finishes), specialist architectural metalwork contractors can supply and install. Always confirm: the full SHS designation (size, wall thickness, grade S355, hot-finished or cold-formed); the standard (BS EN 10210 for hot-finished); and that a mill certificate is provided confirming material conformity.

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