Frequently asked questions
118 questions about QSteelCAD and light gauge steel. Each answer links to the full topic.
118 questions
Program and setup
What QSteelCAD is, what it does and what it does not do.
What is QSteelCAD?
QSteelCAD is CAD/CAM software for light gauge steel and prefab buildings. It builds panels and the roof from your DXF plan and writes every profile to your rollforming machine file. It is a Windows desktop application developed by RENMAE Teknoloji ve Yazılım.
Who is QSteelCAD for?
Is the program available in English?
Yes. The interface runs in Turkish and English, and every command has a name in both languages.
Does it do structural calculations?
QSteelCAD runs production checks: error check, minimum length, clashes and model audit. It also flags joints that need an engineer's approval.
Structural adequacy, including bracing and section choices, is for the project engineer to approve.
Which Windows versions does it run on, and how long is setup?
It runs on Windows 10 and Windows 11. The setup wizard installs everything it needs; setup takes about a minute.
What should you look at first when choosing light gauge steel software?
How your own plan passes through the program to your machine. Ask for the demo on your own plan, not a sample project, and follow one profile from the plan to the production file.
Is LGS software the same as cold formed steel framing software?
Yes. LGS stands for light gauge steel, also called cold formed steel. The real difference is not the name but whether a program draws, calculates, produces, or combines these.
Does steel house drawing software also give production files?
It depends on the program. With a tool that only draws, the profile list and production data are prepared separately. Before you buy, ask whether the output is a file your machine reads.
Can light gauge steel software replace the engineer?
No. The program builds the model and runs production checks. Structural adequacy, including bracing and section choices, is for the project engineer to approve.
Can light steel panels be drawn in general CAD?
They can. But the profile list, hole and notch dimensions and machine data are prepared separately. Every manual hand-off is a step where a drawing error can reach production.
Do you still need general CAD with light gauge steel software?
In most teams, yes. The architectural plan can be drawn in general CAD and moved across as DXF; light gauge steel software turns it into panels and production data.
What is the difference between CAD and CAD/CAM?
CAD draws and models the design. CAM produces manufacturing data from that model. In light gauge steel, CAD/CAM means the profile on screen and the line sent to the machine come from the same record.
Plan to model
DXF plans, wall panels and panel tools.
Which files can I open?
DXF floor plans, including binary DXF, MLINE, ELLIPSE, SPLINE and dynamic blocks. The program does not read DWG; save the file as DXF in AutoCAD and open it.
Can I open DWG?
The program does not read DWG. Save the file as DXF in AutoCAD and open it.
Does corner bracing affect the structure?
Yes: corner bracing adds wall steel, about 9% with Zigzag and 6.5% with K in the sample house. Brace adequacy is for the project engineer to approve.
Which panel editing tools are there?
Bracing, lintel bracing, K braces, continuity, parallel member, cut, split profile, trim/extend and doors and windows are on the PANEL tab.
Is a model without clashes structurally correct?
No. A clash check verifies geometry. Load capacity, connections and the load path are verified separately.
Should a CAD program do the bracing calculation?
That depends on the program's scope. What matters is that a program that does no calculation does not show its drawing as if it were approved. Geometry status and engineering status should be kept apart.
Why is bracing not built in some bays in QSteelCAD?
It is not built if the bay intersects an opening, is too narrow, or already has another brace in the same place. The program writes the reason.
Roof
The plans Automatic roof works on, and its checks.
Which plan shapes does Automatic roof handle?
Rectangular plans as well as L, T, U and H plans. Small recesses don't split the roof; recesses that can join the roof are hatched in the plan and join it when clicked.
Where do ceiling joists start?
From the wall in every room: first the initial spacing from the settings, then the regular spacing. It can be turned off in the ceiling panel menu.
Does the program check truss adequacy?
The program flags joints such as girder trusses that need an engineer's approval. Structural adequacy is for the project engineer to approve.
Production
Rollforming files, machines and counts.
Which rollforming machines does it work with?
The program writes production files for rollforming lines that read .bde lines. Rollform-80, 90, 140, 200 and 300 profiles come ready, and stations switch on or off per profile.
Let's check your machine's line format together in a meeting.
What do the codes in a production line mean?
h: rivet or screw hole, f: flattening, n: notch, s: and l: small and large service hole, w: swage. Positions are in millimetres from the profile start.
How are rivet and screw counts produced?
The rivet / screw count on the CALCULATE tab counts positions without duplicates per profile; screws are twice the number of h: holes. The table pastes into Excel.
Presentation and takeoff
Renders, furniture, quantities and cost.
Do I need a separate program for presentations?
Renders with cladding, roof cover, rooms and furniture come from the same model, and quantities and cost export as CSV. Save images as PNG, JPG or BMP and the model as GLB.
Where do prices in the cost calculation come from?
You enter the unit prices. Where a material has no price, the program does not guess; it shows “enter price”.
How is furniture placed?
By room type, with rules: the TV faces and lines up with the sofa, the rug goes under the bed, doorways and clearances stay free.
Buying and support
Demo, licence, pricing and updates.
How does licensing work?
The licence is activated online and tied to one computer. While the program is open the licence is checked regularly; it keeps running for 7 days without reaching the server.
Get in touch for packages and pricing.
Do updates affect my projects?
Updates keep your licence, settings and projects. Structures in older projects are recognised by newer versions, for example older double-collar K braces.
How can I see QSteelCAD?
Request a demo. We show the program live on the sample house or on your own DXF plan, from plan to production file.
How much does QSteelCAD cost?
We do not publish a price list on the site. Let's talk through packages and pricing in a meeting, together with the licence options.
Can I download the program from the site?
There is no public download on the site. To see the program, request a demo or write to us.
Where can I write for support?
Write to info@renmae.com. Demo and support requests go to the same address, and the reply comes from it.
2027 regulation
Effective date, scope, panels, floors, fire and modular buildings.
Is it the 2026 or the 2027 regulation?
It is the same regulation. It was published in the Official Gazette on 17 May 2026 and takes effect on 1 January 2027. On this site we call it the 2027 regulation, after the year it takes effect.
When does the light steel regulation come into force?
On 1 January 2027. Article 5 of the regulation gives this day as the date of entry into force.
What is the full name of the regulation?
Regulation on the Design, Calculation and Construction Principles of Light Steel Buildings. It was published in Official Gazette No. 33256 of 17 May 2026.
Which institution issued the regulation?
The Ministry of Environment, Urbanization and Climate Change. The enforcement article also names the Minister.
Which buildings does the regulation cover?
Prefabricated, hybrid, modular and on-site profile light steel buildings. Calculation of fatigue effects is outside the scope.
Does TBDY 2018 Section 10 become invalid?
The annex of the new text says that in seismic design this regulation applies in addition to the TBDY rules, and it refers to TBDY Section 10 for panel capacities. The two texts are read together.
Is there a transition period for ongoing projects?
We did not see a separate transition article in the published text. Clarify the status of your project with the project designer, building inspection and the relevant authority.
What is the minimum stud thickness in the new regulation?
At least 0.9 mm for load-bearing studs. At least 0.8 mm for the top and bottom panel tracks.
What is the minimum yield stress in light steel?
250 MPa. Purlins, façade girts and non-load-bearing studs may use 220 MPa.
How many g/m² of galvanizing does my province need?
Annex 1 Table 1 divides the provinces into two classes: at least 180 g/m² and at least 275 g/m². You can find your province with the lookup tool in the regulation guide.
What is the new rule for bracing?
Bracing members are placed as one continuous member between the top and bottom track members of the panel, and their ends are also connected to the studs together with the tracks.
Is fire design required?
Section 11 describes fire resistance design, and Table 10.1 lists it as a separate check item. Performance is shown by test or by calculation.
Where can I get the PDF of the regulation?
The download section of the regulation guide has an unaltered copy of the Official Gazette annex. The binding text is the one published in the Official Gazette.
Is the regulation guide on this site official?
No. It is an independent guide prepared by RENMAE. It does not replace legal or engineering advice.
Does QSteelCAD check conformity to the regulation?
No. QSteelCAD does not perform load-capacity calculations and does not give conformity approval. It performs production-oriented checks; adequacy rests on the project engineer's approval.
Which regulation applies to light steel buildings in Turkey?
TBDY 2018 Chapter 10 is in force today. From 1 January 2027 the Regulation on the Design, Calculation and Construction Principles of Light Steel Buildings also applies, in addition to TBDY for seismic design.
Are the values in these articles up to date?
Each article shows its publication and update date. Check values against the official text on your design date before you decide.
What is the maximum stud spacing?
For sheathing to be accepted as load-bearing, the maximum stud spacing is 625 mm. The load calculation may require a smaller spacing.
What is the horizontal bridging spacing?
Table 10.1 asks whether bridging is placed at no more than half the panel height. For panels with strap bracing, TBDY 2018 10.4.3(d) also requires a spacing of at most h/2.
Which screws connect the bridging?
At each connection point at least two No. 8 or higher-class screws are used.
What is the deflection limit in a light steel floor?
L/200 for general use and L/250 under live load only. It is L/300 if the floor carries brittle finishes and L/360 if it rests on members that show no ductility.
What should the vibration frequency of a light steel floor be at least?
The regulation requires the floor natural vibration frequency to be at least 8 Hz.
What is the minimum joist bearing in mm?
40 mm. This value is the same in TBDY 2018 10.5(e) and in the 2027 regulation.
What is the maximum joist spacing?
The regulation gives no general spacing; if the vibration conditions cannot be met, it requires joist spacing of less than 40 cm and at least two bridging members.
Is light steel fire resistant?
Resistance depends less on the profile itself than on the layers that protect it. The regulation requires performance to be shown by test or by calculation.
At what temperature does steel lose strength?
According to Table 11.1, the yield strength factor falls to 0.88 at 300 °C, 0.68 at 400 °C, 0.45 at 500 °C and 0.28 at 600 °C.
Which fire test standards are cited?
EN 1365-1, TS EN 1365-2 and TS EN 1364-1. Section 11 cites these standards for load-bearing walls, floors and roofs, and partition walls.
How many storeys can a modular light steel building have?
The regulation gives a height limit, not a storey count: in a system carried by modules alone, the building height is at most 14 metres. Taller buildings must have a rigid core.
Is adding a light steel storey to a reinforced concrete building hybrid?
If more than one construction technology is used structurally together, the definition corresponds to a hybrid system. For an addition to an existing building, the existing structure must also be assessed; this decision belongs to the project engineer.
Is there a quality control requirement for a module factory?
Yes. Section 12.1.7 requires production and quality control to be carried out at factory dispatch and documented.
Zinc coating and materials
Yield stress, sheet thickness and coating by province.
How many g/m² of galvanizing for İstanbul?
In Annex 1 Table 1, İstanbul is in the high-corrosion class: at least 275 g/m².
How many g/m² of galvanizing for Ankara?
Ankara is in the low-corrosion class: at least 180 g/m². If water, soil or industrial effects are present, the environment is taken as high corrosion.
Which class are İzmir, Antalya and Bursa in?
All three are in the high-corrosion class: at least 275 g/m².
When does the zinc coating table apply?
The regulation takes effect on 1 January 2027. The table is included in the annex of the regulation as Annex 1.
Are Z275 and 275 g/m² the same?
Coil order codes depend on the manufacturer and the standard. Check how the value on the certificate was measured and compare it with the value in the regulation.
Can DX51D be used in light steel?
Not in load-bearing studs. The regulation expressly excludes the types from DX51D to DX57D for load-bearing studs.
How thin can the sheet be in light steel?
The range in the text is 0.45 to 4 mm, but load-bearing studs additionally require at least 0.9 mm.
What is high-ductility material?
Material with an elongation at fracture of at least 16%. Between 10% and 16% it counts as normal ductility and its place of use is limited.
Bracing systems
X strap, K bracing, bridging and TBDY 2018 rules.
Which types of bracing are used in light steel?
X strap bracing, K and V profile bracing and zigzag layouts. Figure 10.2 of TBDY 2018 shows these examples. Sheathed panels are a separate lateral system.
Who chooses the bracing?
The project engineer. Bracing type, section and layout affect the load-bearing capacity of the building.
Which is the best bracing for light steel?
There is no single best brace. The choice depends on load, panel width, openings, connection detail and production capability. Before shape, the path of the force and the ductility class of the chosen system should be settled.
Can a light steel wall work without bracing?
A wall that carries lateral load needs either bracing or structural sheathing. For sheathing to count as structural, the stud spacing, screw pattern and section conditions of the regulation must be met.
Are the layouts in Figure 10.2 approved standard details?
No. The figure shows examples of braced panels. Section, connection and anchorage are calculated separately for each project.
Why are braced panels counted as Limited Ductility Level?
TBDY 2018 10.2.1.2 places buildings whose entire earthquake load is resisted by braced panels or gypsum-board-sheathed panels in this class. The class affects the coefficients used in the calculation and the permitted building height class.
Does X-strap bracing carry compression?
No, a thin strap is assumed not to carry compression. When the load reverses, the opposite diagonal goes into tension and carries the force.
Should the straps be connected where they cross?
That depends on the detail of the system. Whether there is a connection at the crossing is read from the project detail; straps appearing to cross in a drawing does not show a shared node.
Can the strap be used on one face only?
It can. TBDY 2018 10.4.3(a) then requires the T·e moment from eccentricity to be included in the stud calculation.
How is the strap width chosen?
It is calculated from the panel force, steel grade, thickness and the net section check. It is not taken from a photograph or another project.
Is K-bracing or X strap better?
Neither is better in general. K-bracing leaves the surface flat and carries compression, but needs buckling and node checks. X strap is light, but needs tensioning, eccentricity and end connection checks. The decision is made with the load and detail of the project.
Why does the stud matter in K-bracing?
If the node sits on a stud, the stud carries the sideways force together with the vertical force. Its calculation is not the same as that of a stud without a node.
Do noggins remain in a K-braced bay?
That depends on the layout used. In QSteelCAD the K command removes the noggins in a full-height bay.
Which chapter of TBDY 2018 covers light steel?
Chapter 10: Special Rules for the Design of Light Steel Building Structural Systems under Earthquake Effects.
What is the T·e moment?
When the strap is on one face of the panel, the strap force T acts at a distance e from the stud axis. This product creates an additional moment in the stud and enters the stud calculation under 10.4.3(a).
Can bridging replace bracing?
No. Bridging holds the stud; it does not bring the lateral load of the building down to the foundation. Bracing does not take over the duty of bridging either.
Is a steel strap in the floor a diaphragm?
Not by itself. A strap is sometimes placed to restrain a joist laterally. The diaphragm duty is read from the design definition and the connections.
Load path and connections
Diaphragms, hold-downs, gussets and openings.
Why does the load path matter so much?
Lateral force travels like a chain, and the weakest link sets the behaviour of the system. Strong bracing does nothing if force cannot reach it.
Can connection details be copied from another project?
They should not be. Strength changes with thickness, screws and force. Each connection is calculated for its own project.
How is the load path shown in a drawing?
The members and connections the force passes through should be traceable in order: diaphragm connection, panel, chord stud, anchor. The detail or a reference for each link should be on the sheet.
Must a braced panel be in the same place on every storey?
TBDY 2018 10.2.1.4 requires load-bearing panels to be arranged one above the other on all storeys. A different layout requires the force transfer to be resolved separately.
Is the same load path used for wind and earthquake?
The path mostly runs through the same members, but the magnitude of the force, its distribution and the coefficients in the calculation differ. Both actions are checked separately in the project.
Can a panel be built without a hold-down?
In a panel that carries lateral load, TBDY 2018 10.3.1.5 requires a tension force transfer anchor at the chord studs. Partition walls that carry only vertical load or are not part of the lateral load system are assessed separately.
How many shear anchors should there be?
There is no fixed number. The code asks for as many as will transfer the shear force. The number is calculated from the force and the strength of the chosen anchor.
Can the same anchor carry both tension and shear?
One bolt can see both forces, but the two forces and their interaction are checked separately. This does not mean a single connection in the panel solves both; the duties are defined in the project detail.
Does every brace need a gusset?
No. In some systems the strap connects directly to the stud and track. Whether one is needed is decided by the magnitude of the force and the connection calculation.
How is the gusset thickness chosen?
It is calculated from the force to be transferred, the screw pattern and the local strength of the plate. Thickness is not taken from a photograph or another project.
Is adding more screws always better?
No. Adding screws can reduce the net section and break the edge distance and screw spacing rules. The screw group is designed together with the direction of the force.
Does an OSB-sheathed floor count as a diaphragm?
It can, if the sheathing and its connections are designed to transfer the force. The name of the material alone is not enough; the regulation requires the transfer to be shown by calculation.
Does a trapezoidal sheet floor act as a diaphragm?
Whether the sheet works as a diaphragm depends on its section, fastener spacing and edge details. The regulation lists trapezoidal sheet among the floor system materials; the behavior is verified in the project.
What happens if the floor opening exceeds 3%?
TBDY 2018 gives 3% as the limit below which no separate calculation is needed. The 2027 light steel regulation requires the floor to be modelled as a shell element and the load transfer mechanism to be shown when this limit is exceeded.
Is a brace below a window of any use?
The regulation ties shear capacity to full-storey-height segments. The segment below a window is not counted. The member there may have been placed for another purpose; its role is defined in the project.
Is lintel bracing part of the lateral load system?
Lintel bracing forms the piece above the opening. Whether it is counted as part of the lateral load system depends on the project calculation; it is assessed separately under the full-height rule.
Should stud holes be included in the calculation?
Yes. TBDY 2018 Annex 10A requires hole losses to be taken into account in the section calculation. If the hole diameter / web ratio is below 0.38, the hole effect may be neglected. In the new regulation the limits are in Section 10.1.
Can holes be made on site?
First talk to the manufacturer and the project engineer. The hole must comply with the rules and the area around it must be repaired against corrosion.
Erection and site
Checklist, temporary props and strap tension.
What are the most common erection mistakes?
The three we focus on most in these articles: unplanned temporary stability, loosely fixed straps and bracing cut on site.
When should the checklist be filled in?
While a defect can still be corrected. Screw and connection checks happen before the lining closes the wall.
Is Table 10.1 mandatory?
Section 10.3 of the 2027 light steel regulation states that Table 10.1 must be used to check on-site fabrication and erection. The regulation takes effect on 1 January 2027.
Who signs the Table 10.1 checklist?
The table does not define a signature field. Inspection responsibilities are determined under the building inspection provisions of Article 4 of the regulation. It helps to have a responsible person and date field on your company's form.
How is a sheathed wall checked?
The check must be made before the sheathing is closed. For connections that cannot be seen afterwards, photos and records tied to the panel ID should be kept.
When are temporary props removed?
After the permanent lateral load system and the diaphragm are complete, in the order given in the erection plan. Removing them early, before an area is finished, leaves the panel unsupported.
Can a prop be used instead of permanent bracing?
No. A prop is placed for erection; it is not part of the permanent load path and does not enter the building's lateral load calculation.
Do trusses also need temporary support?
Yes. Section 10.2 of the 2027 regulation requires slender wall panels and trusses to be supported with temporary bracing before the permanent diaphragm action exists.
How taut should strap bracing be?
There is no universal value. The instructions of the chosen system and the project detail govern. Tension is set together with the plumb and alignment check of the panel.
Can a strap that has gone slack be corrected later?
It is corrected by the method the system instructions allow. Cutting the strap on site and reconnecting or splicing it changes the end connection; consult the project engineer first.
Can the strap be checked behind the sheathing?
Hardly, once the sheathing is closed. The check should therefore be made before sheathing and recorded.