Door Manufacturer in China for Global Projects
When buyers compare steel doors, door leaf thickness is often one of the first specifications they notice. A 70 mm door appears more substantial than a 50 mm door, while a 90 mm door is commonly positioned as a premium option.
However, thickness alone does not determine whether a steel door is strong, secure, sound-resistant or suitable for a project.
A thick door leaf can still use thin steel skins, weak hardware or poor bonding. Conversely, a thinner door manufactured as a properly engineered and tested assembly may outperform a thicker but poorly matched product.
The practical rule is:
Door leaf thickness must be evaluated together with the steel skin, core, reinforcement, frame and hardware.
Door leaf thickness is the finished thickness of the door leaf measured at its edge or main reference surface.
For example:
This measurement should not be confused with:
A 70 mm door leaf does not use 70 mm steel. Its external steel skins may be only a fraction of one millimetre thick, while the remaining thickness comes from the folded edge construction, core and internal space.
For doors fitted with external MDF, aluminum or other decorative panels, TOF Door normally states the thickness of the structural door leaf separately. The decorative panels are not included unless the specification explicitly says otherwise.
Embossed steel doors may have raised or recessed patterns that extend beyond the main surface. For this reason, nominal door leaf thickness is normally based on:
It should not normally be taken from the highest point of a decorative embossing.
For custom orders, the approved sectional drawing is more reliable than a general catalogue description.
A nominal dimension does not always equal the exact physical measurement.
Based on TOF Door’s manufacturing experience:
In parts of the export market, suppliers may use 90 mm and 100 mm somewhat loosely when the two versions have similar pricing and positioning. This is not a sufficiently precise basis for a contract.
Buyers should confirm:
The safest wording in a quotation is:
Door leaf thickness: 70 mm
For orders in which the exact dimension is important, the quotation should also refer to an approved drawing.
The following ranges reflect common market configurations and TOF Door’s export experience. They are not universal international standards.
| Product category | Common door leaf thickness |
|---|---|
| Economical metal door | 45 or 50 mm |
| Economical security door | 50 mm |
| Standard steel entrance door | 70 mm |
| Mid- to high-end security door | 70 or 90 mm |
| North American residential steel door slab | Approximately 44–45 mm |
| Steel fire door | Commonly around 45–50 mm, subject to the tested construction |
| Italy-style armored door structural body | Commonly around 70 mm |
| Turkey-style armored door | Commonly around 70 mm |
| Luxury or customized steel entrance door | 90, 100 or 110 mm |
The Steel Door Institute’s SDI-100 specification illustrates why global comparisons require care. Its standard commercial steel-door system covers 1-3/8-inch and 1-3/4-inch doors, approximately 35 mm and 44.5 mm, with different construction grades. These North American commercial dimensions should not be treated as universal residential entrance-door dimensions. ANSI/SDI documents and SDI-100 overview
In TOF Door’s current export orders:
The popularity of 70 mm is not determined by one technical factor. It represents a practical balance between:
This makes 70 mm a flexible specification for many apartment, commercial and mid- to high-end residential projects.
Increasing door leaf thickness creates more internal and external design space, but the actual result depends on how that space is used.
A thicker door leaf can accommodate deeper embossing and more substantial edge profiles. This is one reason why 90 mm and thicker doors are often used for luxury residences and villas.
The added depth can improve the visual presence of the door, but appearance should not be confused with verified security or performance.
Thicker door leaves generally offer more space for:
However, every hardware component must match the door thickness. The square spindle connecting the handles is one of the components most frequently supplied too short when the door thickness is not confirmed correctly.
Even when the steel skins remain unchanged, increasing the distance between the two door faces can contribute to greater overall rigidity when the edge construction, core and bonding are properly designed.
The improvement is not automatic. A thicker internal cavity with poor bonding or insufficient support may still produce an unstable door.
A thicker door usually requires more filling material. Depending on the product, a 70 mm door may use:
These materials are not restricted to one door thickness. Most combinations can be customized.
PU is generally more suitable for 90 mm and thicker doors in TOF Door’s experience, although this is a product recommendation rather than a universal technical rule.
No.
Many residential security doors use folded steel skins and localized reinforcement rather than a complete internal steel skeleton.
A typical door without a full skeleton may still include:
For some 90 mm luxury doors, an internal steel skeleton can be added as an option. Whether it is necessary depends on the door size, weight, design, hardware and intended performance.
Therefore, buyers should not assume that “90 mm” automatically means “steel skeleton inside.”
They should ask directly:
Does the door include a full internal steel reinforcement structure, localized reinforcement only, or no additional steel skeleton?
Usually, increasing thickness can improve stability, but only as part of a coordinated construction.
A thicker door may provide:
However, resistance to dents depends more directly on factors such as:
TOF Door has encountered products advertised as 90 mm luxury doors that used approximately 0.7 mm steel skins and generally weak construction. Their overall quality did not match the premium impression created by the thickness figure.
A 90 mm door is not automatically better than a well-engineered 70 mm door.
Door leaf thickness can contribute to a stronger construction, and thicker premium doors are often paired with better locks and hardware. But thickness alone cannot prove resistance to forced entry.
Security depends on the complete system:
If all other components remain unchanged, increasing only the door leaf thickness should not be presented as a major security upgrade.
For projects requiring verified burglary resistance, buyers should request the applicable test report or classification for the complete door assembly rather than rely on marketing descriptions such as “thick,” “heavy-duty” or “security door.”
A thicker door can create more space for sound-absorbing material and may improve sound insulation. Nevertheless, core selection and the complete sealing system can have a greater influence than thickness alone.
Based on TOF Door’s Intertek testing experience, rock wool achieved the strongest acoustic performance among the tested core options and could outweigh the influence of door leaf thickness.
Acoustic performance is also affected by:
The Steel Door Institute likewise recommends specifying acoustic doors by verified performance, such as an STC value, rather than selecting them only by core material. Steel Door Institute acoustic-door guidance
Therefore, a buyer requiring sound control should ask:
What is the tested STC rating of the complete door assembly?
—not simply:
How thick is the door?
Not necessarily.
A thicker door may contain more insulation, but thermal performance depends on:
A 90 mm door with internal voids and poor sealing may perform worse than a properly engineered 70 mm insulated door.
Where thermal performance is contractually important, buyers should request a tested U-value or other applicable performance result for the complete assembly.
A thicker construction can provide more space for fire-resistant materials and may support a longer fire-resistance design. However, it does not automatically make the product a fire door or establish a fire rating.
A genuine fire-rated door must follow the tested or certified construction, including:
TOF Door’s steel fire doors are commonly around 45 mm, but their performance comes from the tested assembly—not from being thicker than an ordinary door.
A buyer cannot freely change a certified door from 50 mm to 70 mm or from 70 mm to 90 mm and assume that the original rating remains valid. UL provides Product iQ for verifying certified products and assemblies, while its follow-up services assess ongoing conformity with approved requirements. UL Solutions certification resources
The correct principle is:
A thicker door may support a fire-resistant design, but only testing and certification establish the fire rating.
Door leaf thickness may have some influence on overall rigidity, but air permeability, water tightness and wind resistance depend mainly on the complete door system.
Important factors include:
For exterior projects, buyers should evaluate the declared or tested performance of the complete assembly. Door leaf thickness alone cannot establish weather resistance.
As a door becomes thicker and heavier, its hardware must be upgraded accordingly.
TOF Door’s common residential configurations are:
| Door leaf | Common hinge configuration |
|---|---|
| 50 mm | Three 3-hole hinges |
| 70 mm | Four 5-hole hinges |
| 90 mm | Four reinforced 5-hole hinges |
These are TOF Door’s common configurations, not universal rules. Door dimensions, weight, usage frequency and hardware design may require further upgrades.
Additional hinges or higher-capacity hinges can be specified, but reducing the normal configuration is not recommended.
The following components must also match the door thickness:
A complete hardware schedule should state the applicable door thickness before production.
Increasing door leaf thickness normally requires corresponding changes to the frame.
Depending on the design, adjustments may include:
A 70 mm door leaf does not mean that the wall must also be 70 mm thick. Door leaf thickness and wall thickness are different dimensions.
A 50, 70 or 90 mm door can often be installed in the same wall opening by adjusting the frame depth or wall-covering section. Buyers must still confirm:
If the buyer supplies only the phrase “70 mm door,” there is not enough information to begin production.
Door thickness also affects logistics.
For doors of comparable external dimensions, TOF Door’s typical 40HQ loading quantities are approximately:
| Door leaf thickness | Approximate 40HQ quantity |
|---|---|
| 50 mm | 330 sets |
| 70 mm | 260 sets |
| 90 mm | Fewer than 200 sets, depending on configuration |
The actual quantity depends on the door size, frame packing method, hardware, palletization and packaging.
Moving from 50 mm to 70 mm can therefore reduce loading capacity by roughly 70 sets in this example. Buyers should calculate the delivered cost per door rather than compare only the factory unit price.
Yes.
A thicker door normally increases:
Heavy doors are also more sensitive to incorrect adjustment. If the hinges, frame or installation are inadequate, the door may experience:
These risks can be controlled through proper engineering, hardware selection and installation guidance.
For ordinary residential projects, a 90 mm door may be unnecessary. It is generally more suitable for luxury apartments, villas and premium entrance-door programmes where the visual depth, hardware and overall construction justify the specification.
These recommendations reflect common TOF Door applications. Final selection should be based on project requirements.
| Application | Typical recommendation | Main consideration |
|---|---|---|
| Economical housing or rental property | 50 mm | Cost control and standard residential use |
| Standard apartment entrance | 50 or 70 mm | Match market positioning and security configuration |
| Mid- to high-end apartment | 70 or 90 mm | Greater stability, visual depth and hardware capacity |
| Villa entrance | 90 mm | Premium design and more structural space |
| Bedroom or interior steel door | 50 mm | Lower weight and sufficient internal use |
| Hotel guestroom | 70 or 90 mm | Acoustic system, appearance and usage |
| School or hospital | Around 70 mm | Frequent use and stronger matched hardware |
| Commercial project door | Around 70 mm | Project-specific durability and hardware |
| Fire-rated door | Commonly around 45 mm | Must follow the certified construction |
| Coastal or humid environment | Often around 70 mm | Material and corrosion protection matter more than thickness |
These values should not replace a project specification or a certified construction.
Increasing door leaf thickness is not the first priority.
Buyers should normally consider:
A thick cold-rolled steel door with inadequate surface protection may still corrode.
Prioritize:
Increasing thickness can help, but it is not a substitute for an engineered acoustic assembly.
Prioritize:
The entire opening must resist attack together.
Yes. TOF Door can develop customized thicknesses according to the buyer’s CAD drawings and project requirements.
However, non-standard structures may require:
Where the requested construction differs substantially from standard production, an MOQ of approximately 3,000 pieces may be required.
Certification-related products must be treated separately. A customized dimension does not automatically fall within an existing UL, CE, fire, acoustic or burglary-resistance scope.
When comparing a 50 mm door with a 70 mm or 90 mm door, check at least:
Two doors described as “70 mm steel doors” may have completely different structures, costs and service lives.
Door leaf thickness is useful, but it is only one part of a steel door specification.
A 50 mm door can be suitable for an economical residential project. A 70 mm door offers a versatile balance for many apartment and commercial applications. A 90 mm door provides more design and structural space for premium products—but none of these dimensions independently proves security, sound insulation, weather resistance or fire performance.
The most reliable purchasing principle is:
Door leaf thickness must be evaluated together with the skin, core, reinforcement, frame and hardware.
When performance matters, confirm the complete assembly through drawings, component schedules and applicable test or certification documents.
No. The 70 mm dimension refers to the complete door leaf. The steel skins are much thinner and must be specified separately.
No. It may provide greater structural and design space, but actual strength depends on the steel skins, folded edges, core, reinforcement, bonding, frame and hardware.
In TOF Door’s export experience, both 50 mm and 70 mm are common, with 70 mm used slightly more frequently. The answer varies by product category and market.
It can help, but the core, seals, frame, threshold and installation may have a greater influence. Buyers should request the tested STC rating where acoustic performance is important.
Not automatically. Thickness may support a fire-resistant construction, but only a tested or certified assembly establishes the fire rating.
No. Door leaf thickness and wall thickness are different. The frame can usually be customized to suit the wall.
A 90 mm door is commonly selected for premium villas because it supports deeper designs, heavier hardware and a more substantial appearance. The complete structure must still be evaluated.
It can be. Many standard apartments are adequately served by a properly configured 50 or 70 mm door.
The quotation should separately state door leaf thickness, steel-skin thickness, core, reinforcement, frame, hinges, lock and other hardware.
Not without confirming that the change remains within the applicable certification or obtaining the necessary technical approval and testing.
