As with some of my other articles, please be warned, this is a LONG write up showing the processes of installing this particular floor covering, in a particular circumstance, using a full bond method of installation. I’ll be noting all the products used and the reasons for using them. You will gain a huge amount of information from this article, however, this is not a cut and paste ‘how to’ guide. There are often many factors that dictate a wood floor installation process, hence, they often differ. If you’re serious about knowing how this process is carried out throughout the installation from start to finish, then sit tight, make yourself a strong coffee, and read on..
Ted Todd Calico engineered wood flooring was the product of choice for this project (The methods in this article are not exclusive to this product). It’s a 15 mm thick European Oak timber. You can find out more by clicking here. There were primarily two methods of installation on the table. A ‘floating’ method (which means the flooring will be sat on top of an underlay with the tongue and groove locking mechanism to be glued with a D3 PVA adhesive). The second was a ‘fully bonded’ method (Glued directly to the sub-floor). As our client required a firm, solid, and quiet feel to the floor when walked on, the fully bonded method of installation was agreed. Although, this method hugely effected the cost of materials and labour as well as increased the installation time considerably. Well worth it though..
The area to be installed was a large lounge, adjoining office/snug, and an entrance hallway. During the project, the property (a bungalow) was going to be occupied, which added another dynamic to the approach.
Let’s get started
The first process was to remove the original carpet and underlay to expose the sub-floor below. As is visible, the sub-floor was made up of two types. Concrete (the pale area) and Ashpalt (the black area).
It’s helpful to understand that the Ashpalt portion of this floor, is around one inch thick and not bonded to the concrete below. Due to the brittle nature of Ashpalt and the fact it isn’t bonded to the concrete below in any way, it had to be removed. The reason for this being that engineered flooring expands and contracts. It is subject to a co-efficient ratio. In other words a kind of domino effect or multiplication factor, where if all the planks were to expand by Y millimetres, and there were 30 rows, the total expansion of the floor as a whole would be Y x 30. On large rooms, this type of co-efficient or expansion ratio must always be considered, especially when the floor covering is to be glued directly to the sub-floor. The greater the expansion ratio, the greater the shear forces applied to the sub-floor through the pull of the adhesive. With the size of area within this project, this may well have resulted in the engineered floor lifting the Ashpalt resulting in a complete failure of the floor, and huge expense in rectification work. A gamble we were simply not going to take. Therefore, the Ashpalt needed to be removed. Hence, the reason for separating the area from the rest of the property with plastic sheeting taped to the doorways in an attempt to keep any ensuing dust from contaminating the current living areas.
Time to lift the Ashpalt
Contrary to popular belief and most thinking this is a difficult process, well, it isn’t. It can be easily done with a little elbow grease and several tools such as a hammer (To start a hole in the Ashaplt), large crowbar or breaker (To ease the Ashpalt up). As it is a brittle material, almost like glass in some respects, it breaks up with little effort considering.
The next step once the Ashpalt was removed was to deal with the aftermath.
I wish we didn’t have to lift the Ashpalt
Once the Ashpalt is removed, we are left with a damp residue consisting of sand, bitumen, and such particles. This stuff always requires removing, the next task to do so pretty much being the worst part of this entire project.
The residue (visible in the picture as a misty black colour) mustn’t be left down as, again, we’re dealing with shear forces when the engineered wood floor decides it wants to expand. Therefore, any weak or poorly adhered points in the coming layers will result in failure of the floor. Our chosen method of removal was to grind the residue off.
Grinding is carried out with a specific floor preparation machine accompanied with commercial extraction equipment. It’s always important to contain the type of airborne dust this process creates as there can be traces of asbestos within it.
The other huge benefit of grinding, was to remove any loose particles and contaminants from the concrete beneath the residue and the other newer concrete in the other half of the area (As can be seen in this picture).
Not visible in the series of pictures, but disposable clothing was worn during grinding of the Ashpalt residue area. A must should anyone be tackling this type of project themselves. I would also advise some sort of physiological examination.
We also had several high spots of concrete to remove. It’s extremely important to do this as any high spots, if left, will result in a hump/bump in the finished flooring, or a massive amount of smoothing compound being applied to the rest of the area to compensate for the high spots. It’s often far cheaper to simply grind any high spots down.
After the grinding it was time to let the air clear and think about the next stages. The concrete was looking pretty and resembling something we could start to work with. There was an old fire hearth base that you can just see at the far end of this picture (in the background – a lot clearer in the next pictures). This was actually a lot higher than the rest of the sub-floor and frankly impossible to grind as it was so thick. It had to come out..
After we dug out the concrete hearth it was time to fill the hole. This was done with a concrete mix. The product being Ardex A38, a rapid hardening, rapid drying moisture tolerance cement. It needed to be rapid hardening in particular as shrinkage during the curing process over the period of a month – which is what conventional concrete mixes can often do – was an absolute no no. The entire area was going to have a liquid damp proof membrane (DPM) installed at a later time and anything to compromise that was not going to happen.
There were also small but stable cracks in this area that had to be ‘chased out’ (Cut deeper and into a wedge shape), to accommodate Ardex A46, which is an external repair mortar. Sorry, no pics. You can see one of the pre-chased cracks in this picture, appearing from the bottom left to the center.
The main transition
As you can see in the middle of this picture, there is a distinct difference in the height of the concrete – noted where the colour/tone of the concrete changes. This was due to there being different concrete slabs that had been installed at different times in the properties evolution. The slab closest being installed at a later date than the furthest, and being installed at a height to meet the Ashpalt we removed earlier.
This and several other areas within the property like this were nothing to act on now, but would require consideration later on.
Time to clean the area as a whole by mopping several times to remove as much dust as possible. Once dry, we were then ready to apply the first layer of liquid DPM..
F-Ball F77 liquid damp proof membrane
F-ball F77 liquid DPM is a moisture suppressant product that prevents moisture emissions of up to 98% relative humidity coming from the slab, damaging the final floor covering. It must be applied to a thickness of 250 microns to achieve this sort of protection.
The older slab (beneath the Ashpalt) was laid prior to the 1960’s, a time when sheet DPMs weren’t used beneath concrete slabs. This leaves the possibility of rising moisture through the slab. Some areas of concrete were new (within two months old), therefore were not adequately dry for this type of installation. These two factors are the reason for using a full spec liquid DPM system.
Where there are any transitions between new and old concrete and the potential for movement, we typically strengthen these by using mesh (Clearly visible here in blue).
With this particular installation, I decided to install the mesh after the first coat of DPM, and fix it by applying a second coat. This was done to prevent any breaks in the first DPM coat and to make absolutely sure, there would be no failures. In the next pictures, you’ll note the mesh is darker due to the colour of the second DPM coat.
The mesh, still slightly proud, would add a huge amount of strength to the compound that would be going over it.
Once the DPM was dry, and within 24 hours of it being installed (No primer required within 24 hours), we then commenced with the process of building the lower area up (where the Ashpalt once was), to meet the higher slab..
F-Ball 300 smoothing compound
Due to its high compression rating (hardness), we opted to use F-Ball 300 smoothing compound (Seen in the picture as the pink bags). By many professions in the trade, a compound with a high compression value is considered a requirement when adhering a wood floor to it, an opinion we do not contest.
After using our trusty lazer level to work out the approximate height the compound needed to be at for this stage, we cracked on. Due to the thickness of compound at this stage, we incorporated a fine aggregate (dry stone chippings – Quartz – white bags in the picture) to add even more strength to the compound (A requirement stipulated by F-Ball).
Something that isn’t very visible on the pictures (you can just see a white band – Dam – around the perimeter of the black DPM) is the use of a dam to prevent this layer (and the next layer) of compound from coming into contact with the original slab beneath the DPM by means of overflow. If the compound were to bridge the DPM and come into contact with the slab or any brick work situated below the properties damp proof course (DPC), the compound would wick any moisture from the slab. Resulting in the potential failure of the finished floor covering, particularly around the perimeter of the floor.
First layer of compound and aggregate applied, time to leave it to dry. Due to the thickness, this process took over four weeks. During that time, the compound was tested using the British Standards humidity hood method (several boxes placed – visible as a small yellow box in the picture).
Time to prime
After the initial compound was dry, it was then time to prime the entire area. For this we used F-Ball P131 primer (Green pigment). This was applied neat to the exposed area of DPM, and diluted in stages onto the pre-built up area of F-Ball 300 compound.
Once the primer was dry, we would then be ready to apply our final finishing and levelling coat of F-Ball 300 compound. The accurate coat!
Here we can see the installation of compound while it’s wet from the front door view. As the clients were still occupying the property, make do planks were placed for access between rooms. Yes, an absolute health and safety nightmare!! Nobody was harmed or suffered any long lasting effects due to the making of this floor, except me through stress 🙂 It would be around two hours before the compound was foot dry..
Again, you can just see the all important dam on the left of the ‘walk the plank picture’..
We now have an extremely FLAT sub-floor. Now we were left with a final sub-floor that could be worked with and (once dry) were nearly ready to start the installation. This picture taken during the initial drying stage. Hence, the wet patches further back in the picture.
Shall we start fitting? Not yet!
Once the compound has fully dried, we must then bring in the gorgeous Ted Todd flooring to acclimatize. This is bar far one of the most important steps. Wood flooring is often stored in warehouse conditions prior to being sold. These conditions are a far cry from a lived in home. Wood changes its physical dimensions to suit the climate around it. We call this equilibrium or gaining equilibrium. Becoming one, if you’re a hippy type.
Please excuse the quality of some of these pictures. I’m a floor fitter, not David Bailey.
To allow the flooring to become one with its environment, we must leave it in the area to be installed for a minimum amount of time (Stipulated by the manufacturer of the particular flooring). If we didn’t do this, there’s a fair chance the flooring would expand or contract excessively once installed. Resulting in all kinds of problems.
Air humidity reading were also intermittently taken as a matter of course. This was to make sure the moisture in the air was stable and within reasonable tolerances. Should air moisture readings prove to be high/low (below 40% RH/above 60% RH), then further monitoring would be required as well as actions to both identify the reason why the air humidity was high/low, and address it if need be. It’s worth noting some geographical locations will naturally have high/low levels of air humidity. This isn’t an issue per se, as long as the humidity levels are stable. Large differences in air humidity can create issues for this type of flooring.
Now it’s time to get started!
Firstly, the compound is lightly scored in sections (The areas we will be working with – This can also be done to the entire floor in one). We tend to use a grinder with a diamond cup disc briskly skimmed across the surface of the compound. A buffer with course sanding pads does the same thing. The reason for this is firstly to remove any loose material and to key the surface with a view to aiding adhesion of the wood floor adhesive we will be using. The surface is then lightly wiped with a clean damp cloth to remove any dust. Any dampness is then aloud to flash/dry off (this will only take a few minutes with good air flow).
Once we’re happy with the preparation of the surface, we then rack out (place on the floor dry – with no adhesive) the first sections of the floor, making sure we have balance in the area, and the floor is running straight. ‘Trammel lines’ can be used for this, however, I find using the eye in this instance is much more effective, rather than being dictated to by math. The reason being the focal lines (the way the floor will look) of a floor are often more important than blindly following pythagoras. I can feel all mathematicians glaring at these words in disgust. Maths is an important aspect of our/my daily working life. However, when you have properties that are often set out wonky (from room to room), you learn to trust your experienced eye over the numbers, sorry.
Once happy with our racking out, reference lines are drawn on the sub-floor and the engineered floor is dismantled in order. It’s then time to blow/wipe off any dust generated from the racking out process and apply the adhesive. We use a 6 mm V notched trowel, initially (on the first rows) in a fan pattern for strength, then later we complete the fan pattern by applying the adhesive – in larger sections – in a figure of eight pattern.
On this project, we used Rewmar MS Polymer wood floor adhesive. An excellent modified silicate adhesive, that allows the flooring to expand and contract freely.
Bedding down for the night
Now we carefully bed the planks into the adhesive, giving each placement a twist and downward pressure along all of the planks to promote full contact between adhesive and the back of the plank. These initial rows are then weighted (We use boxes of the flooring at this point) to help keep constant downward pressure and contact with the adhesive while curing is taking place. Partly the reason for this being that wood planks of any type can be very slightly bowed or out of shape. Not necessarily an issue (unless the bowing is extremely bad), but any slight bowing can create spring or in other words, an upward force. Resulting in the contact of the adhesive and plank being compromised (no contact). The weight is to remove the possibility of this happening. Please note, the weighting in the picture is not how it finally looked, therefore do not copy. Weight should be added evenly and appropriately as to the pace of the installation.
This is then left overnight (If this part of the installation is done later in the day) or for several hours (If done in the morning), till the adhesive cures adequately. We would then have a solid start to proceed with the rest of the installation. As you can see in the pictures, we also apply tape across the floor to keep the joins together while curing. The tape is easily removed the day after. I’d always advise to remove the tape no more than a day after as it tends to bake on to the face of the flooring, resulting in it being a lot harder to remove. I’ve never had tape blemish the surface of the timber, even when through circumstances, it’s been left on.
Rinse and repeat
Once the starter rows are set, the process above is simply repeated. I suppose that kind of makes it sound more simple than it is. There are so many other little things I could talk about, like undercutting door frames, header (short end of the boards) alignment, colour variations (being picky about where certain planks will be going), ways to cut the wood etc. However, as I mentioned in the first paragraph, this really isn’t a ‘how to’ guide. I wrote this article really to show some of the processes and approach involved, and give a broad incite to this type of installation.
Again, my apologies for the quality/exposure of the pictures.
It’s probably pretty obvious to you that the floor will need to be walked across after the adhesive has been applied and the flooring installed. Most of the time it’s impossible not too I’m afraid. We tend to keep this to a minimum, particularly after a few hours of the flooring being installed, a key time of the adhesives curing process where skins develop but the adhesive hasn’t gone off properly, so any break in contact now due to foot traffic, can be problematic. I don’t tend to mind too much early on, as when the adhesive is wet the passing back and forth (weight) helps bed the adhesive to the back of the boards. We don’t use a heavy roller, as with a 6 mm V notched trowel depth, if the boards are bedded correctly when applied, there really is no need. Although, there is absolutely nothing wrong with using a roller to help bed the boards.
The final hurdle
Once the floor had been installed and adhesive allowed to cure, we finally finished off by installing a basic four inch torus skirting and door bars etc. This particular Ted Todd engineered flooring comes pre-finished. Therefore, there was no need for it to be sanded, filled, and lacquered/oiled. Just a simply clean, and it’s ready to go!
Should you wish to see these picture more closely, most browsers have a zoom option. You’ll just need to ask Google how to find this for your browser.
Crack open the Champagne!
This is the time when our clients finally get to kick us out and regain their lives back! After the realization kicks in that we’ve not actually taken up squatters rights, relief pours over their faces and an imaginary brass band plays a jubilant ditty. It’s an emotional time and one that needs to set in with the soothing sound of silence. The project is over. The desired results are now fact. A gorgeous wood floor that is a pleasure to walk on with an equally stunning appearance. Well worth the epic efforts.
I have to commend you for getting this far! I hope you’ve taken something away from this article and trust it’s not negative. It’s hard to explain why this type of installation is worth it. You can’t feel the floor, you can’t see it properly – especially with my photography skills. Please rest assured that over the easier alternative of a floating floor, this method really does ooze quality and satisfaction. With every step, you’ll know you’ve had it done right!
Whether the colour and style of floor resonates with you or not, after your tastes have been met in the selection process, the way it’s installed will mean everything to the final results.© Copyright 2016 Wes, All rights Reserved. Written For: Fitmywoodfloor