Wood Block Flooring Installation Guidelines

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Woodblock installation guidelines and suggestions:

Take the time to read these please! Call or write with any questions and we can ‘take council’ to find the right answers. Head off problems before they exist! In our industry, carelessness or poor work can be very expensive. We make great blocks; so if you do a great job of putting them in, we will both be happy! 

This information is for general guidance only. 

You and/or your installer will be the final arbiters of proper procedures and methods necessary for a successful outcome. Please take extreme care to follow all necessary steps and precautions to assure a successful outcome. Choosing a licensed, experienced professional is highly recommended. Old Wood LLC will NOT be liable for damages, expenses or ancillary costs related to installation. Old Wood LLC will be responsible only for the actual defective blocks as delivered for six months from date of delivery. All applicable NWFA (National Wood Flooring Association) guidelines for installation of wood flooring should be followed to avoid problems and to stay in line with our warranty which is published at: www.douglasfirfloors.com.  We belong to the NWFA and will generally agree with their advice, however they are limited in terms of wood blocks in particular. Wood blocks have been used for literally centuries - from castle courtyards in Austria - to rail yards and factories around the world; including wood bricks in industrial applications. 

These wood blocks are tough, long wearing, easy to live with and easy to replace in small localized areas. If you exercise good tradecraft, aesthetics, and just plain do a good job, you will see a great result. Take the time and exert every effort to do a good job and reap the benefits. 

Let’s review the proper set up for a successful outcome:
I am not a professional floor installer and do not represent myself to be one. This is a compendium of things I have learned from other professionals and from experience and testing in our plant. Your best and final warranty will come from from your licensed, insured flooring professional. I recommend working with only NWFA or equivalent certified, experienced professionals. Please be sure that your installer has read this and is aware of our warranty and its limitations. 
Old Wood LLC guarantees every block to be suitable for use and will replace any blocks that are not. Old Wood LLC is not liable for errors, omissions or outcomes from these instructions; which are intended only to be helpful guidelines. Our full warranty is published at: www.douglasfirfloors.com

To start out: 
Blocks are brittle and quite fragile prior to being glued flat on a floor; at which point their strength is along the vertical axis along the ring structure. Blocks should be fairly strong but a strong person can generally easily crack them along the rings. Decide individually as you go along - if each block is appropriate. Some minor bark on corners of our Pinon blocks and some others is considered appropriate and useable. If the bark stays on with a gentle pull or wiggle, it will remain in place for many years once installed and is a sign of the true small diameter beauty of this product. The wood is harvested from small diameter trees which are essentially shrubs. A little bark is a sign of the excellent, green, sustainable nature of this product. The bark may be thought of as a type of Cork. Loose or too much bark? Cut the block in half and use the good half of it. This is considered appropriate and normal. Any defect which you believe will cause failure should be thrown out and we will replace it if you are unable to complete the installation - with the amount of blocks ordered for the stipulated square footage. Some blocks contain insect holes from the beetle’s which are killing our Western Forests. (typically the Epps Engrave Beetle). These are considered ‘single emergent’ species meaning they will NOT inhabit the wood like a termite or other wood feeding insect. Consult a pest control expert if you have doubts! Most users consider the occasional worm hole as a sign of the environmentally friendly nature of this product. Again, you decide. 

Some cracking in blocks is normal and is not reason to reject them. What you might want to do if a block has spread from a larger crack: is to set a site table saw to the specified size or average size of all blocks and just zip off any un-squareness. Blocks tend to open up from the crack and you can square them up without actually changing the overall size significantly. We hope this is not necessary and is usually uncalled for. Do what is necessary to avoid problems later on. If you have some of these cut-ups, save them and use them at edges and in less seen or travelled areas. Put the most attractive blocks into the sight lines and main areas of your jobsites floor plan. Use less attractive ones where they will be strong enough but not in the area most viewed. Some half blocks are included in your bundles: they may be used scattered throughout, used to start and end runs, as edges etc. Use them well and they are a plus to the overall effect.
This is all part of the Art of the Job. If this seems excessive to your installer or they roll their eyes when you say this to them, my advice is to find another installer. This is a craft and a trade and aesthetics MUST enter into it. 

Let’s get technical: 
A decent grade, modern, calibrated moisture meter is a must for this job. They are available on-line or from most good hardware outlets. Some are pricey but not necessarily better. When you get below 10% we are really splitting moisture hairs. Your cheek can detect moisture better than any other part of your body. 

What is your ambient moisture in/on the jobsite this time of year? 
We will try to match your blocks to your site conditions before shipping if you share that information with us. Very importantly, please allow us to dry the blocks until we feel they are fully and properly dry. This step will save you having to acclimate on site in nearly all cases. If we are rushed, the burden of drying adequately will be fully on you. It’s like baking a ham; use a thermometer to be sure it is properly cooked - even if you have ‘set the timer’. We use moisture meters to be sure the wood is dry enough. 
You should check your blocks and be absolutely sure they are at 12% or less, preferably 8-10% before starting out. Some desert or very dry mountain locations may require 6% moisture. If this is the case; inform us prior to shipping and we will take extra steps to get the blocks bone dry.
If your blocks need acclimating, they should be carefully spread in an airy but not sunny, clean, dry location. They should be turned by hand or with a careful use of a clean edged square point shovel at least twice a day. Do not install blocks that exceed your installer’s parameters for moisture. No block over 12 % should be used unless you are working in a swamp. The only exception to this is that some extremely pitchy blocks may read slightly higher, (sap is generally not considered a defect; it may create some stickiness but does not harm the structural properties of a given block) Sap can be easily removed with a light paint or household thinner or purple soap type product.

We make every effort to properly dry and season the blocks prior to shipping, but the final decision to install or to further acclimate is your choice. Be aware that any gapping afterwards will NOT be grounds for warranty claims. This is a critical decision on your part. When in doubt, measure, measure, dry, dry. The blocks MAY need to humidify; if this is the case, they typically regain 2-6 percentage points of moisture within one day. Measure and be certain, because some resist drying more than others. Any good moisture meter set to the pine setting will be adequate; however, we prefer the radio sonic type. 

Is the jobsite all closed in and the heat/AC on? This is important! 
Is the slab dried fully? What % is it at? You can test it simply by taping a 3x3 sheet of clear plastic onto the slab in a sunny area. If any moisture accumulates within 24 hours, it is not dry enough.
The Slab should be below 12% moisture. Is the Slab adequately flat? Blocks can work very well with cracks and uneven surfaces but extra care will be required. 

Are all the wet trades finished inside yet? They should be. Paint, plaster etc. can add damaging moisture to the environment. The floor should be the last thing to go in before you hand the keys to the owner.

If fixtures, appliances etc. are to be installed after the floor is installed, take EXTRA caution by applying heavy protective paper or a specialty product made for the purpose. These are available at good flooring supply sales outlets. Your installer will know where to purchase these. Spend the extra few cents per foot to assure a scratch free surface greets your Grand Opening! Inform trades persons and installers that THEY will be held responsible for damage to the floor and work with them to avoid it in the first place. Use large wheeled roll trucks if necessary to move heavy objects across the floor. Consider laying out wood or other runners if necessary to avoid ‘spreading’ the blocks which can show up later on as ladder cracks or worse, loose blocks. 

Before starting out, assure the slab is flat to industry standards, dry, clean, free of oils or solvents or other substances which might hinder glue adhesion or create health issues later on. 

Test all products separately and in combination, several days before starting work. 
Does your glue really stick to the slab (this should be obvious but is often taken for granted!)?
Glue a test block in a location where you won’t be sorry if it leaves a bit of residue when you remove it. Do this where you can attempt to break it or knock it off after the glue has set for three days or more. The test should be with a rubber mallet or wood block. Don’t ‘point fracture’ the blocks but do give them a good pounding. A floor scraper should be able to remove the block when you are finished! We will gladly send you dry test blocks in advance of your order if you request them. 

Glue: We recommend Bostiks Best or Sika Bond. I have used these and other glues in tests in our plant and the only one I don’t really like is Liquid Nails as it is too hot and skins up way to fast. Use a ¼” notched trowel or other per your installer’s instructions or the glue manufacturer’s instructions. Be sure to get properly sized ridges. A flat spread glue surface is NOT permitted. When applying the blocks, being sure to give a slight ‘wiggle’ onto the blocks to assure proper adhesion and to avoid skinning of the glue from preventing bonding. A twist/wiggle and a tap to set each block. Be sure your glue can cure properly. See below:

Sanding: Let the glue cure fully per manufacturers specs before ANY SANDING TAKES PLACE. (Usually at least two to five days.) 
A rectangular vibratory sander will avoid creating the tiny lines in this very hard material. The problem is that drum sanding leaves these lines which are not readily seen until staining takes place. Additionally, vibratory sanding is easier on the glue joint in most cases. Drum sanding may be done but very carefully and take extra care to avoid any sudden dragging or shocks. 

Filling: depending on filler to be used; fill before or after staining.
Make your own tests to be sure which procedure will yield proper results. 
You may opt to use commercially available filler such as Timber Mate or other of your choice. Make test samples to be sure the filler will not improperly color or stain the block itself. End block really grab color! 
You may want to consider using a paste made from your own site-collected sanding dust and linseed oil. We can talk about this if you choose to go this route.
Alternatively you may choose to use a paste made of cork powder and boiled linseed oil. 
This ‘concoction’ can go on before or after sanding, allow it to dry partially, then re-apply before or after staining depending on color.
If you do a rough oil-wood-dough filler application before sanding, the dust from sanding itself goes into the cracks and helps seal the gap. Then a second, squeegeed application after sanding (before or after staining), will give a good complete crack seal with a product that becomes like cork in a weeks’ time. This can be covered with urethane or other linseed/Tung oils ( I won’t vouch for some of the new ‘one coat’ Euro Oils) and will give a flexible long lasting fill. Additional sanding dust should be kept in a can or a bag for future repairs or touch-ups on site. Label properly or somebody will wonder what the heck it is and throw it away! Old Wood LLC can also provide this powder and we may have a packaged product available soon. 
www.woodblockfloors.com 888-545-9663

Whichever way you go, be sure to test to see which sequence yields the desired color outcome. Sounds complicated but only takes a few minutes with stain and blocks in hand. Let’s sweat the details up-front for a great, trouble free, long lasting floor. 

Stain: 
Apply stain sparingly in several coats. Avoid excess stain running into the cracks where it can react with the adhesive and create ‘bleed up’ of degraded adhesive. End block absorbs a lot of stain. Let it! This is one of its best attributes for commercial flooring in that the color wicks deeply into the grain allowing for scratches and scrapes to remain colored as opposed to planks which typically only take stain several thousandths deep at best. 

Top Coat: the final finish may be oil or urethane (water based or oil). If you used an oil-dust paste mixture, you have probably already oiled the surface! If you have oiled it, prior to using urethanes, lacquers etc. - create a test area. Most urethanes, oil, and water, will adhere well to some linseed/Tung oil; however, any excess oil needs to be removed. If it shines, remove it with a light rag and thinner cleaning. Heavily applied oils dry to a very tough surface and can be difficult to remove. Apply in thin coats only, wiping off any excess to avoid this. 
Bona Traffic has always worked well for us but you may prefer another brand such as Pacific Strong or Street Shoe. A two part, oxygen cross linking water based product, will surely give good results. Old Masters Water Based urethane has worked well for residential use and could serve as a base coat; however, they do lack a two part , commercial grade product. 

Oil finishes: Oils such as Water Lox or other more expensive brands may also be used to good result. Test for color. Old Wood LLC makes a very lovely smelling product called Old Wood House Oil Blend. Call for pricing. 
Will the customer be willing to re-treat periodically? Will the slight odor from oils be a problem? Oils build up and create a lovely durable finish that is also good for the wood so may be very well used. Single coat, ‘mono coat’ and other new Euro Oils are interesting but are tricky, ‘arcane’ and very expensive. One we do like is Bio Shield Hard Oil #9. The company also has Aqua Resin Floor Finish and a great wax top coat, which is being used by some very high-end clients with environmental and planetary concerns! www.bioshieldpaint.com or (800) 621-2591 . 

Please, please, keep me posted on the products you choose and what kind of results you get. 
For more information please go to : http://www.woodfloors.org/ I am available to consult on any aspect of the work and look forward to an excellent, durable and beautiful outcome.