What finish should I ask for on my beams?
If your beam is going to be used in a situation where appearance is important such as house interiors, halls etc - Visual Appearance Grade A should be specified. If you require a sanded finish, please specify. Non visual grade is intended for use where the product is not seen and occasional chips and voids are acceptable.
What strength grades should Glulam be designed to?
The Glulam standard, AS/NZS 1328 states grades from GL8 to GL12, Prowood is certified to produce PL8 and PL12 grades.
Will CCA treated Prolam cause corrosion on galvanised fixings?
While this may be a problem with solid unseasoned timber, Prolam does not act in the same way. Because all Prolam is manufactured from material is kiln dried after treatment, the treatment salts are throughly fixed into the timber. They will therefore not subsequently leach out or affect galvanised fixings. For additional protection it is recommended that lots be greased before inserting into CCA treated Prolam beams that are exposed to the weather.
How long should I keep the wrapping on?
Wrapping of Prolam beams is primarily to protect them from marking during handling and transport. This is not designed to be a waterproof protection. Once on-site water can often get in under the wrapping and cannot get out. Wrapping should be slit to provide drainage. Wrapping can be left on Prolam beams for as long as possible (even during construction) to protect against accidental marking. Also be aware that partial removal of wrapping to access connections may cause patches of discolouration by exposure to weather.
Do I need special connections for my beams?
Prolam can be treated as natural solid timber when it comes to fixings. The use of standard nailing systems and bolts is normal. In exposed situations dark stains can appear from the use of unprotected steel brackets and bolts. Use galvanised metalwork where there is any possibility of moisture.
Can finished Prolam beams be re-cut and drilled?
Any cutting, drilling or slotting that exposes unsealed timber must be protected with an application of appropriate weather or treatment sealer. Avoid cutouts, rebating or drilling in the top and bottom edges of Prolam beams. These could cause serious weakness in tension and compression areas. Consult the manufacturer or designer first.
Do splits along glue lines mean delamination has occurred?
Actual delamination is a failure in the laminating process. While an opening along a glue line may be indicative of delamination there are other more common causes. Typical checking that occurs in large section timber in response to moisture variation will most naturally occur in Prolam along a glue line where the natural continuation of the timber fibres is interrupted. This is often mistaken for delamination.
How serious are checks and why do the appear?
Surface checking and splits occur as timber is allowed to absorb moisture then dries out in response to environmental changes. Surface fibres are more severely exposed to these changes than the inner core and as a result of the movement in these fibres as they dry and shrink, surface splits may occur. Changes in atmospheric conditions will affect the appearance and disappearance of these checks. The effect of surface checks are superficial only and do not usually have any effect on the structural performance of the Prolam.
How can these checks be minimised?
Prolam beams are provided with a sealer coating if requested, which controls the ingress of moisture into the timber, and is done before the beams leave the factory. If the beams are exposed to the weather for a greater period than 8-10 weeks a further coating should be applied.
Consult our painting instructions for permanent sealing requirement.s
Where can H1.2 treatment be used?
Prolam treated to H1.2 is only suitable to be used in the building envelope as NZS3604.
What is the difference between Visual and Non-Visual grades?
Prolam Visual is made from visually selected sharts that are then finger jointed together into a long length and laminated into the required beam. This grade is recommended for use in highly visual areas and when a paint or stain quality finish is required.
Prolam Non-Visual is made up from stress graded timber and is not visually graded. The non-visual grade is recommended where the beams are not seen.
What is the difference between GL and PL grade?
The Gl prefix is a reference to the old term 'Glulam', where the PL is the prefix for branded 'Prolam" structural timber.
Why is bandsawn finished smaller than standard?
Bandsawn finished Prolam posts and beams are 6mm smaller than standard, because we have to cut the bandsawn finish into the beams after they are made. Use the Prolam Online Calculator to specify this product.
Can you cut drill, machine Prolam after manufacturing?
Yes, because Prolam is pretreated before laminating, all pieces are fully treated, so any cutting etc. does not need apaint on treatment applied to the cut portion. However any cuts can be sealed.