Written by

Danny Neill

Bower Beams: The Ultimate Solution to Repair Dry Rot Damaged Timber Joists

Timber joists are horizontal components used in framing to carry floor loads. Unfortunately, they can suffer from damage caused by dry rot over time, leading to a loss of structural integrity.

Dry rot is a fungal growth that colonizes and consumes timber, reducing it to a brittle matter. This can compromise the safety of a building and necessitate repairs.

Bower Beams, also known as Joist End Repair Plates, are galvanized stainless steel plates that can be used to restore rotten joist ends.

In this article, we will explore the different aspects of Bower Beams, including their functions, applications, sizing, and the damage caused by dry rot.


Understanding Dry Rot

Dry rot is a fungal attack that occurs when moisture levels in the timber rise above 18%. This allows the spores of the fungus to grow and colonize the wood.

In contrast to other wood decaying fungi, dry rot only colonizes timber that has been exposed to damp conditions for several weeks, typically caused by a plumbing leak, faulty rainwater goods, or poor ventilation.

Dry rot is a destructive force that consumes the timber, leaving it in a brittle and structurally unsound state.



Damage Caused by Dry Rot to Timber Joists

If timber joists within a building suffer from dry rot, they will begin to decay from the inside out. This process significantly reduces the timber's structural integrity and can lead to significant safety concerns.

Dry rot can cause the timber to crack, split, and crumble, leaving it unable to bear the load it was designed to support.

A joist with dry rot damage should not go unaddressed as it can lead to building collapse or other forms of structural destabilization. Therefore, prompt repair action is necessary.


Using Bower Beams for Joist End Repairs

If a joist has suffered dry rot damage, it is necessary to address the matter as soon as possible to prevent further damage.

The first step of the repair process is to cut away the damaged portion of the joist. This could significantly reduce the length of the joist, leading to further problems with structural integrity.

In situations where cutting back of the joist has been necessary, Joist End Repair Plates, such as Bower Beams, are utilized to restore the structural strength.

To use Bower Beams for a joist end repair, the following steps are taken:

  1. The size of the Bower Beam needed to repair the joist is determined.

  2. The damaged portion of the joist is cut away, and the remaining portion is measured to determine the length of the L-shaped plate required.

  3. A Bower Beam is placed onto the timber joist, which serves as the replacement end for the cut-out portion.

  4. The Bower Beam is then secured to the timber joist with the use of the included coach screws provided.

  5. This repair process ensures the joist is structurally sound and restores its original integrity.


Sizing your Bower Beams: BM6, BM9, and BM17

Bower Beams are available in three different sizes, each of which can be used for different degrees of structural damage:

  • BM6 Bower Beams: BM6 Bower Beams are suitable for use with joist ends that have been cut back to a maximum of 6 inches. They are the ideal solution for minor repair jobs, where limited damage has occurred.

  • BM9 Bower Beams: BM9 Bower Beams are intended for use with joist ends that have been cut back to a length of up to 9 inches. This size is suitable for more moderate repair jobs, where more substantial damage has occurred.

  • BM17 Bower Beams: BM17 Bower Beams are the largest of the three options, recommended for use in structural repair tasks where the joist end has been cut back to a length of up to 17 inches. This is an extensive repair solution, appropriate for severe cases of dry rot damage.

By providing these various sizing options, Bower Beams enable the best solutions for different degrees of damage.


Carrying Out The Job In Hand

The repair process of damaged joists using Bower Beams consists of the following chronological steps:

  1. Inspection: A comprehensive inspection of the timbers and joists in the building will determine the extent of rot damage and the overall repair work that will be required.

  2. Cutting Back: The size and placement of the area of dry rot is identified, and the damaged portion of the joist is cut back to an appropriate length.

  3. Positioning: The Bower Beams are placed onto either side of the cut joist to provide a stable support system for the joist.

  4. Fastening: Coach screws are used to attach the Bower Beams to the joist, ensuring that the L-shaped plates are seated appropriately and attached securely.

  5. Re-Inspection: The final step is a comprehensive checking process to ensure that the Bower Beams are secured correctly, and that the repaired joist is structurally sound.



Dry rot is a serious problem that can compromise the structural integrity of timber joists in buildings.

Bower Beams provide an efficient and long-lasting solution for repairing damaged joist ends. No matter the degree of rot damage, these galvanized stainless-steel L-shaped plates are available in three different sizes to suit a wide variety of repair needs.

By using the correct size of Bower Beam and following the chronological order of repair, homeowners and building owners can be confident in the stability and safety of their properties.


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Will Ship w/c 29th July