Can they give you the contact details for at least two other recently completed installations in your area?

There is no substitute for recommendation. If you can, you should attempt to talk to the owners. At the very least view the properties from the street.

 

 Do they intend to replace the existing timber boards entirely or cap over the old ones?

If you want the job done because the timber is showing signs of decay then capping would be a false economy. Swish Installers will usually recommend complete replacement as a matter of course and it would be advisable to insist on it in any case.

 

 Are the materials guaranteed not to discolour?

Some manufacturers still use lead as a stabiliser in their formulation. Although not all lead formulas will discolour, the only ones that do discolour and turn 'pink' are based on lead technology. Swish boards are based on a non-lead formula and will not discolour.

 

  Do they include rectification of defective timber in the price?

Many installers will undertake a reasonable amount of rectification without any further charge.