Call Whittlewoods
01488 669 217

How To Fit Solid Oak Flooring

Get a free quote

Request a free, no-obligation quote for wood flooring restorations, repairs and fitting from the Whittlewoods team.

How to fit solid oak flooring

The type of flooring you choose for a room, and how the flooring process itself is done, goes a long way in determining the final appearance of that room. That is why it is important to get the right flooring for your room – and perhaps even more importantly – ensure that the flooring is finished and laid correctly.

Too often I have seen floors that have been improperly laid and the whole floor has had to be lifted, at huge expense and waste.

There are a few key factors that must be taken into account when fitting a solid wood floor.

  1. Height allowance
  2. Subfloor and installation method
  3. Skirting
  4. Quantity to order
  5. Quality and Moisture content of wood on arrival
  6. Acclimatization of the wood on site
  7. Expansion gaps
  8. Direction of boards
  9. Maintenance

Before choosing your floor I ask you to please read our articles on types of solid wood floors and benefits of solid wood flooring.


1. Height allowance: First thing to check is whether the thickness of the new floor and the possible addition of a sub base is going to affect your room in any way. Either by head height on low beams, ceilings or doorways or does this extra height affect the levels to inter leading rooms. Ramped Thresholds are designed to bridge this difference in height between rooms but are only made standard to accommodate a thickness of 20mm anything beyond this will have to be specially made.

2. Subfloor and installation method – First and foremost you must determine what is the existing subfloor that you will be fitting your solid wood floor onto. In all cases you must check moisture level of the sub base. Fit a solid wooden floor anywhere near moisture and you are wasting your time and money. Generally all ground floor bases are prone to moisture problems at some time or other, so adequate moisture proofing is essential. First floors are less prone and less precaution is needed.

Sub bases can generally be broken down into 4 possibilities described below and below that are the different methods of installation:-

a) Concrete floor this includes tiles and linoleum: Check moisture – check if base is level – check if base is sound and not crumbly. If these are all good you can Glue your wooden floor down onto the sub base (see installation method below 1a). Some companies suggest floating a floor on a waterproof membrane (installation method 3a). I would agree with this up to 150mm wide boards but also warn that with the slightest hint of moisture rising you will end up with problems of the floor buckling. If there is moisture you might be able to remedy this with a liquid damp proof membrane (DPM). Or choose engineered boards. Excessive moisture and don’t choose wood at all. Sticky underlay is another option, and does work well but experience is necessary and not suitable for boards wider than 150mm (installation method 4).

If your concrete is not level and is crumbly there are a couple of options for you. First option is if
floor is only slightly uneven, but still uneven enough for the board not to get full adhesion along its length. Use Sika T2 which is a liquid baton (installation method 1b). This should keep the board proud of the unevenness but still allows for good adhesion.

If the concrete is really uneven and crumbly you either need to replace the concrete or an easier method is to fit a chipboard sub base on top on the concrete. This is by far the most preferable way to fit a wooden floor. The Chipboard sub base acts as a membrane and is also a perfectly clean and level surface to either glue or nail your solid wooden floor to. The chipboard is normally screwed down into the concrete using hammer fixings but beware of drilling into any pipes. I you don’t want to use chipboard – wooden batons can be used, as long as you can get them all level and that they have a strong purchase into the concrete. Make sure the batons have been treated to ensure longevity.

b) Chipboard or Plywood: This has been described in the above point, when a not so good concrete has been covered with a chipboard sub base. This method is the Rolls Royce method of wood floor installation as you have the perfectly level surface to fit your wooden floor. Good chipboard also has water resistant properties. You can nail, glue or float a floor onto this sub base with ease.

c) Wooden beams, batons or rafters: Either where an old floor has been lifted or possibly in a new room where the batons have been fixed onto the concrete. Easy installation – either secret or surface nail through the floor boards into the batons (installation method 2a or b). If floor boards have tongue and grooves on all 4 sides there is no problem but if they are not ensure that you cut the boards to the right length so that the joints will meet on top of the batons.

If some of the rafters or batons are damaged it might be a good idea to fit a chipboard sub base as described in the section above on concrete floors. Check if you have enough height allowance in the room to allow for the chipboard and your new floor. If there is any damp issues this is a preferable option as you can either fit a waterproof membrane under the chipboard or on top.

Also use chipboard if you want to reduce noise levels normally associated with a suspended floor.

d) Old existing floor boards: As long as the old boards are good and strong, secret or surface nail floor boards directly onto old floor boards (Installation method 2a or b), it is a good idea to put a sound proofing underlay between the old floor and the new floor. This will deaden sounds and stop any creaking. Like in sub bases a) and c) if the old floor boards are uneven fit a plywood or chipboard sub base, to level things out and give you the perfect surface to fit your new floor.

Installation methods

1. Glue down

This can be done in two methods, a) Full glue – use a notched trowel and sika T54 spread a workable size area of glue, lay your floor boards and then add more glue, working throughout the room b) Liquid batons – use applicator gun and sika T2 sausages apply a strip of glue every 30cm and rest the floor boards onto these. Then apply pressure to get adhesion

2. Nail down

Two methods a) Secret nailing – normally done nowadays with special nailing gun, called a porta-nailer, a nail is hammered in at 45 degrees into the side of the plank just above the tongue and then through into the sub base. b) Surface nailing – a nail is driven in through the surface of the plank and through to the sub base. This nail hole then has to be filled or sometimes special nails called … are intentionally left exposed to create an old fashioned look.

3. Floating

a) As the name suggests the floor is not attached to the sub base by gluing or nailing but is floated on top of it. For this method you will need to use an underlay that you wooden floor rests upon. The boards themselves are glued together at the joints.

4. Sticky membrane

a) This is similar to floating a floor but the underlay used is sticky on one side. But be warned if you are not experienced in this method of installation it is very difficult, as the sticky side is extremely sticky and of you get the board in the wrong place you will have extreme difficulty in adjusting it.

3. Skirting

The obvious way to cover the expansion gap (see point 6) that is required around the edges of your floor. In new builds this poses no problem as you simply fit the skirting after you fit your floor. But what do you do if you have skirting already fitted.

There are 3 options:

a) Undercut – with a special machine slice off the bottom of the skirting to the same thickness as the floor and underlay you are fitting. This now allows you to slide your new floor under the skirting. This is neat and tidy and means you don’t have to remove the skirting and all the decoration associated with that.

b) Remove the skirting and refit on top of the floor after the floor has been fitted.

c) Fit beading or scotia on top of your new floor and up to the old skirting. Your expansion gap will now be under the beading.

4. Quantity to order

To calculate the quantity of timber to order measure the rooms and calculate the square meters, then you must add a minimum of 5% extra on top of your area to allow for cutting and wastage. It seems like an unnecessary expense, but it is unavoidable. The best fitters in the world can’t get around this. If you have lots of corners and small rooms it is advisable to allow 10%. The last thing you want is to run out and then not be able to get matching timber.

5. Quality and Moisture content of wood on arrival

Due to the popularity of wooden flooring, it has become a very big industry. The benefit of that to you the consumer is that it has become very competitive. So good quality wood is available at cheaper prices. The message in this short paragraph is just to say that Don’t necessarily go for the cheapest you can find, for the following reasons. As you can imagine the floor boards have gone through various stages of manufacture from being cut down in the first place to how they are sliced, then they are kilned dried, a very important stage, after that they are machined into planks with tongue and grooves etc. All these stages cost money and if the manufacturer has skimped on these to keep his costs down ultimately the quality of the final product will be inferior. Cheap boards that don’t fit together are not cheap in the long run. Enough said I will now leave it to your judgment.

The moisture content of the wood on arrival at you premises should be between 8% and 12%. It is unlikely that you will have a moisture reader, so will be difficult for you to measure this unless you can borrow or hire one. This is an advantage of using a professional. They can ensure that these factors are correct and it is their responsibility to do so.

6. Expansion Gaps

This is the big one. In my experience people generally tend to underestimate the expansion and contraction properties of wood. When a floor is on the move and there is no space for it to go into, nothing can stop it. It will buckle itself and it will break walls if necessary for it to expand. As discussed in point 5 the wood arrives with hopefully a moisture content of between 8% and 12%, then depending on the ambient environment at different times throughout the year the wood expands and contracts. In winter when all the windows are closed and the central heating is on the atmosphere dries out, as the atmosphere dries it literally sucks the moisture out of the wood, this causes the wood to shrink which can leave gaps in your floor boards. This is Good because during the summer months with no central heating and windows and doors open and generally quite a humid atmosphere the boards soak up this moisture and expand considerably.

Due to this expansion it is vital to leave a gap all around your floor into which the floor can expand, about 15mm is preferable. This gap is hidden under the skirting as discussed in point 3. Please ensure that this gap is consistent all around including doorways. There is no good in having this perfect expansion gap all around but then at the doorway architrave leaving it because it is a bit too difficult, the wood will merely catch here and buckle.

7. Acclimatization of the wood on site

This is a long-debated subject amongst floor fitters and my beliefs are based around natural laws. Acclimatizing wood in a very dry centrally heated room during winter is going to give you problems as it expands in the summer months and conversely putting wood onsite in summer months with all the windows and doors open is going to give you big gaps in the winter months as the wood contracts. Likewise there is no point in acclimatizing wood at any time of year on a building site as this is not the environment that the wood will always live in.

So what does one do – Well these are the ideals: wood arrives from the factory at between 8% and 12% and the ideal humidity of a room for wooden floors is between 40% and 60%. Keep within these ranges when you fit your floor and keep the room at this humidity and you will never ever have a problem with you floor. If the wood is dry fit it loosely so it can expand and if it is wet fit it tightly so that it contracts. Hiring a professional takes this worry away from you, but ensures that your professional gives you a guarantee on his workmanship. In doing so he is stating he is comfortable with his level of skill and knowledge.

Hygrometers to measure humidity levels are readily available. There is not much you can do in summer months to control humidity and very rarely will it go beyond these ranges and if so not for long enough to be of concern. Problems arise in winter when the central heating is turned up and the atmosphere is totally dried up, one or two bowls of water around or even a dehumidifier soon sorts this out. The other biggest problem is when floors are acclimatized into a very dry environment, people tend to want to make sure that their floor is very well cured. So this totally shrunk floor is fitted tightly into its room and looks lovely during the winter, but as soon as summer comes this floor is on the move and will expand so much that no expansion gap is going to cope with it.

Fitting Engineered floors certainly does negate a lot of these problems as they do not expand or contract to nearly the same degree as solid wood.

8. Direction of boards

There is no right or wrong here. And it is generally a matter of taste, but there are a few guidelines. If you are fitting onto existing rafters or batons you don’t have a choice as the boards have to run at 90 degrees to the rafters. General rule of thumb is to run the boards away from the door leading into the room. Looking down the length of the board tends to make the room look larger. Boards running cross ways tend to be jarring to the eyes. Likewise run boards along the longer length of the room, for instance a long hallway with the boards running across the short length looks strange. If in doubt and if you are a little bolder try going diagonal it has a great affect.

9. Maintenance

We have a whole section on how to maintain your wooden floor, and the methods used will vary according to the type of finish you have. Suffice to say here that a little ongoing maintenance will save you a lot of effort and money down the line. Wooden floors are very practical as well as very easy to keep clean and looking great.