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Cellar doors also require your attention

Although cellar doors are not always the centre of attention and are usually subordinate, they also have important tasks.

Basement doors lead inside the building or from the outside to basement rooms. If they are external doors, they should have the same properties as front doors in terms of burglar resistance, fire protection and thermal insulation. Due to their location in the basement, flood protection often also plays a role.

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Käuferle - leading manufacturer of garage doors, enclosures, windows and front doors

Value inside.

As a family business based in Aichach near Augsburg, we develop and produce garage doors, enclosures and partition wall systems, as well as PVC-U and aluminium windows and front doors. Like all Käuferle products, our PVC-U cellar doors also comply with all the rules of technology and craftsmanship in order to protect your assets in the best possible way.

Sustainability through craftsmanship

Our PVC-U cellar doors consist of high-quality door frames, panels, fittings and locks from southern German suppliers. In this way, we support the regional economy and can also improve our CO2 balance through short transport routes. This also results in sustainable products with a long service life.

Customised cellar doors

Like all other Käuferle products, the cellar doors are customised to the customer's specifications and the individual installation situation. This results in door solutions that are just as suitable for new buildings as they are for refurbishments. We also offer a comprehensive range of services. For example, we are happy to support you with planning and tendering.

Thermal insulation and U-values for cellar doors

Why thermally insulated cellar doors?

Thermally insulated building components are generally useful wherever cold wall surfaces, doors and windows meet heated interior spaces - regardless of whether these are basement doors in the house or in the exterior wall. The main problem with a lack of thermal insulation is that warm air meets cold surfaces and condenses there. If this happens over long periods of time, it can lead to moisture damage and mould growth. Thermally insulated cellar doors should always be installed if the surrounding wall surfaces are also thermally insulated.

Thermal insulation and U-values for cellar doors

The Ud value (d=door) describes the thermal transmittance of a complete door. It is decisive when assessing the thermal insulation quality of a cellar door and must be specified by the manufacturers. As a general rule, the lower the value, the better the insulation. According to the German Building Energy Act (GEG), new basement doors that lead from the outside into heated areas in the basement as side entrance doors must have a Ud value of at least 1.8 W/(m²K). Doors with thermally separated door leaves can achieve values of up to 0.7 W/(m²K).

Retrofitting internal insulation to cellar doors?

Newly installed cellar doors to the outside always have good thermal insulation quality due to the GEG specifications, so homeowners no longer need to worry about insulation. If there are moisture problems with cellar doors in existing buildings, they can be insulated on the inside at a later date - regardless of whether they are made of wood, plastic or metal. For example, they can be subsequently filled with blow-in insulating materials. It is also possible to apply insulation boards on one or both sides to improve the Ud value.

Should cellar doors remain open or closed in summer?

Just like cellar windows, cellar doors leading to the outside should always remain closed at high outside temperatures so that warm air does not condense on cold surfaces and thus favour moisture damage. The same applies inside the building if cellar doors lead from warm corridors into cold cellar rooms. Doors with good Ud values, as well as retrofitting insulation, make sense here, but are not mandatory.

Burglary protection, security and fire protection

Basement doors in wood, plastic or metal - which material is best?

PVC-U cellar doors offer the best price-performance ratio for exterior applications. They are low-maintenance, robust and easy to customise - even with glass cut-outs. Cellar doors made of metal (especially steel) have similar properties, but are considerably more expensive, while wooden cellar doors are not recommended due to the moisture that is often present on the outside. In terms of thermal insulation, burglar resistance and fire protection, doors made of wood, plastic or metal are comparable, while design issues are usually decisive for cellar doors inside the building.

Exterior cellar doors are best designed to be burglar-proof

If cellar doors lead directly to the outside or if they serve as connecting doors between underground car parks and residential corridors, they should be of a high quality in terms of thermal insulation as well as burglar resistance and fire protection. The properties of burglar-resistant doors are categorised into seven resistance classes (RC) in accordance with DIN EN 1627: RC 1N, RC 2N and RC 2-6. As a general rule, the longer a cellar door resists a break-in, the higher its resistance class.

Whether you live in an apartment block or your own home - more burglary protection thanks to security bolts and alarm systems

While video surveillance systems only document break-ins, alarm systems and mechanical security devices such as steel security bolts often help to prevent offenders from leaving during the break-in attempt. Steel security bolts fitted to the cellar door are firmly anchored on both sides of the door frame or in the wall when closed. In combination with alarm systems, cellar doors can thus be optimally secured - whether in a block of flats or in your own home.

Fire protection with fire-resistant cellar doors

As cellars often contain high fire loads, it is essential to consider fire protection. If there are building authority fire protection requirements, fire-resistant basement doors, which are usually made of steel, must fulfil the corresponding fire resistance classes T30, T60 and T90. The numbers after the T (door) indicate how many minutes the fire-resistant cellar door must be able to withstand a fire.

Fire protection vs. escape route: Can basement doors in apartment blocks be locked?

Security interests play a greater role in large apartment blocks than in private homes. In basements where there are only storage rooms, no escape routes are usually required by building regulations - in this respect, locking is generally permitted. The situation is different when escape routes in apartment blocks (for example from an underground car park) lead through basement corridors. Such doors, which are often also fire doors, may not be locked - unless they have self-opening panic locks.

Secure cellar doors against flooding

Flood protection with cellar doors

Heavy rainfall and flooding events are becoming more frequent, and so the question of how securely cellar doors protect against flooding is becoming increasingly common. Cellar doors are described as watertight if no water ingress is recorded in 24 hours at tested water levels. They are flood-resistant if less than 240 litres of water penetrate in 24 hours. Waterproof cellar doors for optimum flood protection require special seals and should always be installed by specialised companies.

Securing and sealing cellar doors

It is not always necessary to replace non-waterproof cellar doors with waterproof models. It is simpler and also cheaper to secure cellar doors with flood barriers that can be retrofitted on the outside - such as flood bulkheads, hinged bulkheads or stop logs. If it is only a matter of stopping the occasional ingress of rainwater, it is often sufficient to reseal the cellar doors. Rubber sealing tapes or adhesive sealing tapes, for example, are suitable as sealants.

Options for water barriers for cellar doors

Sandbags already provide good protection during floods with low water levels of up to 25 cm. More powerful water barriers are essential for higher water levels. For dam beams, guide rails are fitted to the right and left in the reveal of the cellar door. However, there are also mobile water barriers that are simply placed in the door reveal and spread out there without permanent fixtures. In this case, neoprene sheathing protects against the ingress of flood water.

Frequently asked questions about cellar doors

Here you will find answers to frequently asked questions about cellar doors:

What advantages does plastic offer as a material for cellar doors to outside rooms?

PVC-U cellar doors are robust, easy to clean and also inexpensive compared to wooden and metal doors.
Should cellar doors have insulation?

This is not necessary for cellar doors inside the building. However, if cellar doors border on unheated outside rooms, they must fulfil minimum requirements in terms of insulation in accordance with the Building Energy Act (GEG).
How can burglary protection for cellar doors be improved?

In general, attention should be paid to high-quality frames, panels, fittings and locks. Additional protection is provided by horizontal, laterally anchored steel security bolts.
Are watertight cellar doors suitable for self-installation?

As with flood barriers, specialised companies should be commissioned to ensure professional installation and, in the event of damage, full insurance coverage.