Richard Aylen elaborates on best practice for assessing and installing reclaimed wood flooring
DURING the past few years there’s been a growing trend towards using reclaimed timber flooring. Clients and designers are attracted by the look of a building material that already has had a life somewhere else, and one that bears the marks, patina and colouring that reflects its history. Customers looking for a unique finish will often consider reclaimed materials.
There can be little doubt a brand-new solid hardwood floor made from timber from certified sources is one of the most sustainable flooring options, but a reclaimed wooden floor is also a sustainable option because fewer demands are made on raw materials, energy and the means of disposal.
As well as wanting a sustainable floor and one with a ‘story’ there are a few other reasons why customers are attracted to the idea of reclaimed flooring.
Reclaimed floors are easier to find than in years gone by owing to increasing demand. If a building containing a wooden floor is demolished or adapted, the owner has a good chance of selling and reusing the floor rather than disposing of it.
This is all good for the environment but maybe not so good for manufacturers of brand-new floors.
The reclaimed flooring market also improves access to exotic tropical timbers which cannot now be bought new owing to the need to preserve rainforests and other fragile environments. The number of tropical timber species used for flooring is many and includes some highly prized timbers such as mahogany and teak.
Years ago, when these timbers were used in high volumes for flooring they were made into a wide variety of patterns including herringbone, mosaic and strip, so there’s a wide choice of formats available, though in the longer term reclaimed floors made from exotic timbers will only become scarcer.
How can contractors and designers respond to demand?
Contractors need to be aware that in many ways, supplying and installing reclaimed wooden floors is different from using brand new material.
At the design and procurement stages you need to be aware that supplies are not constant because reclaimed floors do not flow from a production line. If your customer has a rigid and detailed specification, they may need to allow extended time to source the material and be open to the possibility they may need to pay a higher price if their needs are very specific.
It’ll be no surprise then that procurement is easiest if the client’s requirements are flexible and they are looking for abundant species of wood and floorboard formats.
The waste factor will usually be considerably higher than with a new floor. This is unsurprising perhaps because in any consignment of reclaimed flooring there may be some damaged pieces. Other factors that may influence the amount of waste include water staining, iron staining from steel nails, and splits.
Depending on the type of floor required there may also be a need to decontaminate or clean up the flooring before installing it. Tongue-and-groove jointed planks or traditional floorboards that were laid as a floating floor should be fairly trouble-free as they will not have been glued down or nailed. Boards that were nailed to joists or battens will need to de-nailed, if the supplier hasn’t already done so.
Reclaimed floors that have been glued together (as opposed to glued down) will rarely be reuseable because the tongue and groove joints will usually be too severely damaged when the boards are taken apart. Solid hardwood floors will rarely be laid in this way, but it’s common with engineered boards.
Many woodblock floors will have been glued down. This is often the case with herringbone or chevron pattern floors. Many years ago, common good practice was to carefully dip the blocks in molten pitch or a rubberised floor adhesive, coating only the underside of the block.
If the blocks were laid properly the T&G joints will be free of adhesive and so they should come apart easily. Some older adhesives contained asbestos and so this risk must be assessed when working with these materials.
If the blocks were laid in modern adhesive such as an MS polymer or similar the task of cleaning the blocks can be more difficult and often there may be pieces of screed or levelling compound attached.
The contractor will need to make a careful choice of adhesive for the new installation because not all modern adhesives will work if the blocks are contaminated with bitumen adhesive residues. An old tongue-and-groove jointed floor may have residues of dirt and lacquer/wax etc. in the joints. If this is excessive it should be removed before refitting the boards as this will allow the natural seasonal movement of the floor to take place without the floor buckling or bowing.
It’s often tempting to suggest the old floorboards are put through a planer before installation to ensure they are all the same thickness and to remove surface contamination, but this won’t avoid the necessity of sanding and finishing the floor after it has been laid. The best way is usually to lay the floor with its old surface finish intact, then to sand it to a clean, flat finish after installation.
This also avoids the risk of ruining the blades of the planing machine if there happens to be any stray nails still in the boards. Any minor repairs and cosmetic work can be done before the boards are sanded.
It’s worth bearing in mind floors made many years ago may not have been manufactured to the same close dimensional tolerances we expect today. The original floor would’ve been laid, the joints filled, then it would have been sanded and treated with its final finish.
The floorlayer who relays the floor today may need to replicate this process and be able to adjust the rows of blocks to reduce gaps as the floor is fitted. With plank or strip floors, it must be ensured there’s a balance between reducing gaps and keeping the rows straight.
Large gaps in plank or strip floors must be filled with caution – a floor that’s 100 years old will still expand and shrink as humidity changes during the seasons.
And now to what is probably the most difficult question to answer with any degree of accuracy: ‘What expansion allowances do I leave with a reclaimed floor?’
As Junckers’ technical manager I find I’m being asked this increasingly often, when customers have bought reclaimed Junckers (and other) floorboards. This can be a source of some risk for installers. If you leave too little expansion allowance the floor may buckle. Too much, and the floor will contain excessive gaps at certain times of the year.
The reason it’s difficult to provide definitive advice on expansion allowances is due to the fact that the moisture content of the timber will probably vary and won’t be controlled in the way it’ll be with newly manufactured boards. Even if you were able to fully condition the reclaimed boards to arrive at a uniform moisture content the expansion gaps you’ll need to leave will differ between one manufacturer’s product and another because the board size and format also comes into play, as may the chosen method of installation.
The installer of reclaimed hardwood floors often has to deal with a wide spectrum of moisture levels because the boards will probably have been stored in an unheated environment with little or no humidity control. For the floor to perform properly it needs to be installed with a moisture content that matches the relative humidity in the building as it will be when the building is occupied and in use.
The contractor must then decide what size expansion gaps will be needed at the perimeter of the floor and between the boards or strips.
Expansion allowances may differ according to the type of flooring element being laid. For example, a herringbone block or chevron pattern floor won’t usually require expansion allowances between the blocks but will rely solely on gaps at the perimeter of the floor. Plank or strip floors will usually have gaps between the boards as well as at the perimeter.
Finishing the floor
A reclaimed hardwood floor will usually be sanded back to bare wood and refinished after it has been installed. The procedure and choice of finishing product will probably be much the same as with any other timber floor, reclaimed or not.
With tropical timbers the priming coat of lacquer must be chosen carefully because the natural oils contained in some species can damage the new surface treatment.
A solvent-based primer such as Junckers SB primer usually works best on tropical timber and two coats can be applied if the contractor thinks there’s a particularly high risk of failure.
As reclaimed wooden flooring becomes more popular, contractors and clients need to become aware of the differences between a brand new floor and a reclaimed one. By properly assessing a reclaimed floor’s condition, sourcing the right materials, and understanding how the floor will move in service, contractors can meet the growing demand for sustainable and attractive floors while minimising the risks.
Armed with this knowledge it’s possible to tap into sources of flooring material that offer variety, uniqueness and attractive finishes that reflect the previous life of the floor.
www.junckers.co.uk
Richard Aylen is technical manager, Junckers