Wood You Like F.A.Q. & News

Installing a wooden floor on joists

Andrew Baker asked us the following question (see here for his original comment):

It's a 200-year-old listed mid-terrace cottage. The majority of room still have the original boards, which are in a serviceable condition (which is a great testament to the use of oak in itself). The room I am looking to work in has a few original boards but the majority of it is new ply or pine boards, all covered with carpet.

The existing boards are laid directly on joists. Joists have centres of around 400 to 500mm. All boards nailed to the joists. The underfloor void is about 300 to 400mm high above bare ground. This void is not currently ventilated with airbricks, and while this isn't causing too many problems it is something we are looking to rectify. We are also looking at ways to enable ventilation between the room and the underfloor void.
Being in a listed property, when I replace my flooring it will have to be solid planks (no tongue) and on a suspended floor (ground floor).

So my question is, how does this affect preparation and installation? I'm thinking specifically of underlays (something to protect the wood, not cause condensation and reduce sound transfer, but remain breathable). Also of fixing methods - I would rather not glue (difficult to take up again), and secret nailing will be difficult - what are the alternatives?
Finally, I'm also interested in the choice of wood. I have read 18mm thick wood is not sufficient for a suspended floor?
I hope you may have an opportunity to address these questions, and am fairly sure the answers will interest a broad range of people.
Thanks and regards.
Andrew Baker

Answer (options, tips and issues to be aware off)
Installing directly onto joists above a void (which should indeed have airbricks to insure ventilation especially for removing excess humidity) asks for floorboards that are at least 18mm thick, 20 – 21 mm is preferred. Another issue to consider is the space between the joist: 300 - 350 mm is best otherwise the boards may ‘flex’ too much and could even break/snap.

Normally we would advice solid (or load-bearing Wood-Engineered floorboards) to be installed directly onto the joists by secret nailing in the tongue. If the void underneath is ventilated properly and doesn’t show any signs of moist no extra underlayment is needed.
Ventilation causes air movement = draft, but is important to keep your house climate healthy.
The ‘modern’ construction of the T&G boards allows movement (shrinkage especially) of the boards without feeling the effect of this draft. (Filling gaps between ‘old-fashion’ floorboards is just a very temporary solution, after a while because of seasonal movement the filling material will drop in the void and you can start all over again and again and again.)

Oak floorboards of 21mm thick without T&G can be face-nailed on top of the joists (but note maximum space between joists), as long as every board rests on at least three joists. Because the short sides of the boards don’t have connecting T&G’s for stability between the boards it’s recommended to end every board on a joist.

As mentioned above, non T&G boards can create draft, but we see another problem also: sourcing proper Oak floorboards suitable for installing as floor. These boards need to be dried to floor specifications, which is between 9 – 11% moist. Most kiln and dried timber contains 15% moist.

Can we suggest two other options to consider?

Option 1
Install plywood on top of the joists first, creating a stable and sound subfloor, minimising draft. Using Elastilon’s self-adhesive underlayment you can then install Oak overlay strips (solid wood of 6 or 10mm thick) tightly, which creates a ‘floating’ floor that can be ‘lifted-up’ easier than glueing boards or strips directly onto the plywood.

Option 2
Select ‘standard’ Oak 21mm thick T&G floorboards with square edges (non-bevelled) and with secret nailing install the floor directly onto the joists.
The unbevelled boards will create an ‘old-fashioned’ appearance but the T&G’s will avoid draft and are easier installed.

We hope this answers your questions, we welcome any further comments on this post if you need further advice or have more questions.

Did you install your wooden floor yourself and are you darn proud of it? Enter our DIY-Triumphs contest!

How to lay a wooden floor: Keep it Simple

Installing a wooden floor (solid or wood-engineered) as DIY-er isn’t rocket science, more a case of common sense, patience, using the correct materials and making the correct preparations.

Some things are so obvious we won’t go into them in detail (like buying wood that is suitable to be installed as floor and dry enough, meaning: timber wood – 15% moist or more – isn’t suited and that the room is wind and weather proof, wet decoration work finished etc).

Correct materials and correct preparations:
Quality products might be a little bit dearer; in the end it will save you time, aggravation and possibly even regret and money.

• Make sure you have one type of underfloor and the underfloor is ready (dry, level, - remove existing floor-covering timely enough to make good any defects or unevenness in time)
• Buy the correct underlayment (with the ‘floating-method’)
• Have all the materials in house before you start, make a list of everything you need at least one week beforehand and make sure it can be delivered or collected on time (because some materials just run out of stock, you’ll know Murphy’s Law)
• Make sure all tools you need are in the house, are working, sharp and safe (if you have to hire specific tools, place a reservation on them with the hire company so you’re not going to be disappointed)
• Store the wood in the same area you plan to lay it (or in an area that has the same ‘climate-conditions’ – garages are a definite No No) 2 – 4 days before you start the installation; leave the wood in the packs (if wrapped in packaging material and according to manufacturers instructions, some do differ, most not).
• Clear all furniture out of the room beforehand, dust from sawing will get in anything!
• Remove – if needed – skirting boards, mark them when you do so you know which one to place back where to avoid mix-ups and extra cutting work when placing them back.

Preparations on the day (floating method with standard T&G fixing)

• Ban little children from the room! (And cats, dogs or other pets.)
• Check again if all materials and tools are there.
• Materials: wood, underlayment, pvac-wood glue, spacers, beading or scotia, radiator-pipe-covers, thresholds, cloth (to remove excess glue as soon as you notice) and felt pads (for underneath furniture)
• Tools: hand saw or Jig-saw, tape-measure, square, Stanley knife, pencil (at least three, they disappear in thin air), knocking block + installation bar (both should be part of any DIY installation kit you buy), hammer, heavy duty bin bags, work bench (tool box should do fine also as bench, watch out for sawing into it).
• If needed, remove doors and undercut architrave and/or doorposts (chisel out the last bit).
• Open two packs of wood, check for any damages to the surface, tongue and groove or click-system. If any and on more boards, re-pack as best as possible and return every pack straight back to your supplier for new material or re-fund. In no circumstances open more packs to check for damages, this might render your guarantee useless.
• Check if the boards are straight by laying them with the groove side on the (level) underfloor. Also check for bowing – cupping. Slight bowing (middle doesn’t touch the ground) of long boards is normal, extreme cupping (the ends stand up and leave a gap of over 5cm if turned up side down i.e. top surface faces floor) not.

If everything is OK and in the wood-type, grade and finish you selected mix the two packs to get a natural look and colour, shade mixture (all boards differ in colour and characteristics). During the works, keep checking for surface damages before you install a board, once down and between other boards/rows it’s a pain to remove it. (Murphy’s Law: it will always end up in the middle of the room where you would notice it most - afterwards.)

Do read the fitting instructions (if any) the manufacturer supplied with the floor, some might differ on some points and not following their instructions could render your guarantee worthless. When in doubt, call your supplier.

The basic installation tips underneath are based on laying a wooden floor in a normal straight forward rectangular room without any obstacles or problems and in/under normal circumstances We do know that other shaped rooms will differ, but starting practice and common sense is the same.

Start at the wall that has the fewest doors, bay windows, fireplaces, alcoves or recesses and seems straight.
Lay the first row of underlayment parallel to the chosen wall from one end of the room to the other (when using DPM or Combi-underlayment move the row at least 3 – 5 cm up the walls, mind that you place the Combi-underlayment such way that the overlapping DPM strip is on the room side, not wall side).

Place the first board on top of the underlayment in that corner where both grooves (long side and short side) face the walls in that corner (some instructions state you have to start in a specific corner, use common practical sense).
Glue the groove on the short side of the next board (at the bottom of the groove to avoid glue splurting out above) and connect board one and two, making sure that there is no gap between the joint. A gap at one end of the joint indicates your boards aren’t connected straight. Don’t worry about spacers now.
Install the complete first row this way (use knocking block if needed); keep checking for gaps between the joints. The last board might need to be cut.

Trick of the Trade:

• Place the new board (1) on the last board (2) already down (it will overlap of course) with the short end groove of board 1 facing the wall (that’s the wall it needs to end up to i.e. closest by).
• Carefully slide board 1 till it touches the wall, find the exact spot where short side tongue of board 2 begins (i.e. the real surface of board 2 starts) and mark this on board 1.
• With square and pencil mark the cut line and cut board 1.
• If done correctly the groove of the shortened board should slit in the tongue of board 2, finish the row completely and leave an expansion gap (size of the tongue) at the wall in one go.

Make sure all joints of row 1 fit tightly and straight. Then move row one slightly away from the wall enough to place your spacers and move row one back against the spacers. Once this is done, check joints again.
Making sure your first row is straight is the most important step of the installation.
If needed use extra thin material behind some of the spacers to ensure the first row is straight.

If the remaining left over part of the last board is 30 cm (1 foot) long it can be used as beginning of row two. If the room is a rectangle and your boards are all the same lengths it is best practice to cut some boards in 1/3, 1/2 and 2/3 lengths (make sure you are left with the short end tongue on that part you want to use!) to start a new row in order to prevent creating a repeating pattern every two rows.

Install the rest of the room (install next rows of underlayment as you go, with Combi-underlayment make sure the overlapping self-adhesive strip fits correctly underneath the next row of underlayment).
Glue both long side and short side grooves of all boards before slotting them in place, make sure to glue the whole of the groove length, not just drops here and there.
Remove any excess adhesive with the damp cloth as soon as possible. When needed use knocking block and/or installation bar for a tight fit and keep checking those joints. Place spacers at the end and beginning of some of the rows to keep your expansion gap the same everywhere.
Don’t walk over the just installed boards.
Take a well-deserved coffee or tea break after you installed row four so the glue gets time to bond. Then carry on with the rest of the floor.

Tackling the last row. Not a nightmare (not with standard T&G boards anyway), but common sense and patience will get you there.
You can use the same trick of the trade to cut the exact width for this row (per board), leaving a correct expansion gap and a correct fit.

Remove all packaging and leftover boards etc from the room. Vacuum clean (or use a soft broom) the room to remove all sawdust and little pieces of wood before they can damage the floor when treaded on.
Remove spacers and install scotia, beading or skirting boards in place. Careful with lost/dropped nails or pins; undetected and treaded on they can damage your floor before you’ve even finished.

Remove everything from the room (tools etc) and vacuum clean again. Wait 2 –3 hours before placing furniture back (put felt pads underneath legs to prevent scratches), this way the glue gets time to bond and walking and moving around will not open any boards to create gaps (Murphy’s law: normally in the middle of the room.)

When in doubt, call you supplier or manufacturers help-line.

As mentioned before: these are BASIC tips; all rooms, circumstances vary.
In most other situations the best tip is to think ahead, use common sense and patience. Or feel free to post your specific questions or own experiences here (use the comment link underneath)

Did you install your wooden floor yourself and are you darn proud of it? Enter our DIY-Triumphs contest!

Climate Change: From Parish to Planet

CEPS (Chilham Environmental Protection Society) is inviting everyone to their workshop:

"From Parish to Planet"

on Saturday 10 February (2pm to 5pm) in Chilham (Kent, near Ashford and Canterbury) Large Village Hall (entree free)

"Come and hear what the experts have to say and discuss practical ways that communities like ours can make a difference"

Children are welcome, there will be supervised play activities in the small village hall.

For more information, contact details are on the CEPS workshop website

Case-study: Duoplank on Underfloor Heating

"As self-builders, we are very involved in specifying the materials used in our house.  We wanted the look and feel of real oak planks but without too many of the difficulties associated with the shrinkage of natural oak.  We quickly identified the Duoplank product through its UK distributor Wood-You-Like in Kent. This is an Engineered Board made with a wide top solid layer of natural oak and a high-quality birch ply substrate, critical to us because we were installing on concrete with UFH embedded in the floor. 

We visited the showroom near Ashford and received plenty of good advice from the company and felt we were dealing with people who actually installed the product, as well as supply them. 
From the wide range of oak qualities available we selected the 'Rustic' range as being closest to the effect we sought to create in our new-build, which is a Georgian-style farmhouse of brick and tile exterior.

Installing the product was easier than we expected, the longest task being the selecting and cutting of the planks.  As we tackled each room, we initially placed them in position 'dry' on the floor to check for colour-match and fit.  The planks slot together using a tongue-and-groove formation.  The Duoplank manufacturer had taken care to chamfer the bottom edges of the planking, avoiding any chance of surplus glue seeping into the tongue-and-grooves.  We used a chop-saw to cut each edging plank to length.  This made light work of the cutting task; the engineered product seems as dense as working with solid oak. We glued the rows of board to the floor, three or four at a time.  Wood-You-Like had given us a clear fact-sheet on how to pre-condition the boards and the temperature of the floor during the installation.  This ensures that the boards have a normal amount of humidity on installation.  Unlike a conventionally heated house, using UFH wood flooring shrinks slightly in the winter whilst heat is drawn up through the floor.

Wood-You-Like advised us on the size of the gap to leave around the wall edges - 15mm in our case  - and we used chipboard spacers to maintain this gap and hold the edges firm whilst we glued and fitted each successive row.  We found a notched trowel to be the best tool for spreading the glue evenly.  It was important for us to eliminate air gaps under the boards to maximise heat transfer from the screed into the wood.  We managed this by spreading the glue 'notches' at 90 degrees to the board lengths, which enables one to see better where the boards are not fully seated, as glue oozes out slightly at the working edge.  We used bricks as a temporary method of holding down any 'high' areas of board during setting; this task certainly showed up minor inadequacies in the flatness of the screed subfloor!  Fitting the 25mm wide skirting board around the rooms to cover this gap has completed the finished appearance.

The glue sets in 24 hours and we followed the detailed instructions for gradually applying heat into the flooring to slowly dry out the wood.  During our first winter heating season this has opened up a 1mm gap at many of the board long edges - or about 0.05% total shrinkage compared to the summer state, when we expect the gap to close up again.  We are more than happy with this result over UFH, and our choice of Engineering Board to provide the visual effect that we sought."

John and Julie - West Berkshire

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New in collection: Oak Rustic Wide-Board Oiled

Just in:
Wood-Engineered 'Triplank' Oak Rustic wide-board brushed and oiled natural (micro-bevelled)
4mm Solid Oak top layer on high quality pine-backing, standard T&G fixing.

Only £ 39.95 (ex VAT) per sq m.

Also available lacquered or brushed and oiled white or mocca.