Seal a loft staircase properly and permanently

In order to avoid unnecessary heat loss through an attic staircase, professional sealing is essential. While the stair hatch with the feed frame creates sufficient tightness, the gap between the floor slab and the feed frame creates a weak point about four meters long.

Moisture, steam and heat

Ascending heat and humidity always seek the path of least resistance to escape. The access opening of an attic staircase offers a potential escape route in a closed ceiling. Therefore, when insulating the staircase on a permanently tight closure with insulating effect value must be placed.

Since the structural conditions often burden a frequently occurring temperature difference between unheated attic and heated space below the attic stairs, a professional sealing on moisture and steam must be designed in both directions. When installing the attic stairs, a clean and smooth ceiling level inside the floor must be prepared.

Insulating and sealing agent

In order to optimally seal the gaps between the feed frame and the floor slab, different materials are used:

  • building foam
  • Styrofoam
  • Steam sealing tape
  • Vapor barrier film
  • Dämmzopf
  • hemp fibers
  • Elastic insulating lips

An absolute prerequisite for an optimized waterproofing of the attic stairs is the perfect airtightness. Even with well-filled insulating materials in the joint, an imperfect joint seal by a cover strip can lead to much energy loss.

Combined ceiling connection systems

In the higher-priced area of ​​attic stairs, special ceiling connection systems are integrated, which ensure reliable sealing through overlaps and multi-point closures. This also takes into account the possible temperature differences, which can lead to material deformation and thus impair the insulation effect.

When properly insulating a loft staircase more and more than one insulating material is used. In case of stress, the materials have an additional effect. If, for example, an elastic insulation temporarily stiffened by cold, the seal is maintained by a temperature-independent further insulation.

Annually check for leaks

Once a loft ladder has been properly installed and sealed, it can
be disguised. The heat transfer coefficient or U-value can be checked by measuring for example by a thermal imaging camera. Due to the constant invisible stress of the attic stairs due to rising heat, humidity and temperature differences, a regular annual test should be made on the attic stairs.

Tips & Tricks

In order to detect a possible draft at the joints of the attic stairs, you can use a candle or a down feather to scan the gap around for air movements.

Video Board: How To Replace a Pull Down Attic Stairs