In our attic space, there is a vertical timber support running down from the roof towards the floor level, which is obstructing how we would like to use and finish the space. From what I can see, the support appears to be tied into the surrounding roof structure, but it is not clear whether it is acting as a structural stud, a support for the dormer cheeks or rafters, or simply a trim or finishing piece.
Various online discussions about attic rooms suggest that these timbers often form part of the load‑bearing arrangement transferring roof and dormer loads back into the main structure, and that altering them without proper design can affect the stability of the roof or dormer.
I want to remove this timber down to floor level or replace it with a less intrusive arrangement, but I am aware that any change to existing structural members in an attic conversion needs to be approached very carefully. I’m trying to understand what the typical attic room framing practice is, so I know if it’s a big job or not. Do I need an engineer or building surveyor to review, or will the contractor be able to advise me?
The timber should be treated as structural unless and until a competent inspection establishes otherwise. Its appearance or position alone is not enough to determine its purpose, and even a relatively slender member may be carrying load or providing restraint.
RM Block
A roof window is normally formed within the existing rafters. Where a rafter must be cut, the opening may require strengthened side rafters and horizontal trimmers to transfer the interrupted roof loads around the opening. A dormer is generally more complex and may include cheek studs, a front frame, headers, trimmed rafters and connections to the roof or floor structure. A vertical timber in this location could therefore be supporting a dormer cheek, a rafter or trimmer, transferring load to a beam or joist below, restraining the frame against movement or merely supporting plasterboard. This cannot be confirmed without seeing how it is connected at the top and bottom and what lies behind the finishes.
The scale of the work could range from straightforward removal of a nonstructural lining support to a significant structural alteration. If the member is load-bearing, a replacement arrangement might involve strengthened timberwork, a new beam, revised connections and temporary propping while the work is carried out. Cutting it first and assessing the consequences afterwards could result in movement, sagging, cracking or local instability.
An experienced contractor may offer a useful initial view and can assist with careful opening up, pricing and construction. However, the contractor should not be the sole person deciding that an apparently integrated roof member is redundant. I recommend an inspection by a chartered structural engineer with experience of domestic roof alterations. The engineer should examine the member’s bearings and fixings, the adjacent rafters, dormer framing, floor structure and any available drawings, and then confirm in writing whether it can be removed or provide a suitable replacement detail and temporary works sequence.
A chartered building surveyor can review the wider attic conversion, identify defects or compliance concerns, prepare a scope of work and oversee the project. Where a new load path or structural substitution is required, the detailed design should normally come from the engineer.
The proposed alteration may also have implications under the building regulations, particularly Part A relating to structure. Planning, building-control and certification requirements should be checked separately. If the attic is used, or intended to be used, as habitable accommodation, the review should extend beyond this timber to matters such as floor strength and compartmentation, wider fire safety issues such as detection and escape, compliance of the stairs, insulation, ventilation and condensation risk.
[ Why can’t I enlarge the rooflights in my apartment?Opens in new window ]
As no photographs, drawings or site inspection have been provided, no definitive conclusion can be reached about this particular timber. It should remain undisturbed until professionally assessed.
Damian King is a chartered building surveyor and a member of the Society of Chartered Surveyors Ireland
Do you have a query? Email propertyquestions@irishtimes.com
This column is a readers’ service. The content of the Property Clinic is provided for general information only. It is not intended as advice on which readers should rely. Professional or specialist advice should be obtained before persons take or refrain from any action on the basis of the content. The Irish Times and its contributors will not be liable for any loss or damage arising from reliance on any content
