How to Deal with Floors in Old Homes
While original floors – be they timber, stone or quarry tiles – can be a desirable feature, they can also be problematic. The key to repairing an existing floor or adding a new covering is all about what lies beneath, says Natasha Brinsmead
We explain what you need to consider before repairing old floors or adding new floor coverings in our renovator’s guide
Original floors are often damp, uneven or cold — or all three. Happily, whether you wish to restore these floors to their original glory, or plan on replacing them with something entirely new, there is a solution out there.
The key to working with old floors lies in investigating the subfloor first.
The Importance of the Subfloor
Commonly, the problems thrown up by floors in existing homes, no matter what they might be made of, will stem from what they have been laid on top of — or the subfloor. This subfloor and its integrity is all the more important when it comes to laying a completely new floor covering.
On the ground floor of period houses, it is not uncommon to discover that tiles, flagstones, brick and parquet have been laid on top of nothing more than earth, ash or sometimes sand. Left in their original state, there is no reason why this should cause too many issues other than cold feet.
Problems only tend to arise when they are covered with a new, non-breathable material, or where a layer of unsuitable insulation is added. Old floors were designed to ‘ breathe’; to absorb and evaporate moisture from the whole surface area with no damage to the materials used.
In the case of original timber floorboards, you might well discover that the timber joists that form their underlying structure have begun to rot, while little thought is likely to have been given to insulation.
What’s more, it’s not uncommon to find uneven concrete floors in existing homes, which need be levelled before a new finish can be installed.
Original Tile, Stone or Parquet
In the case of tiles, flagstones or parquet flooring with a base of earth, ash or similar, you have several options.
One is to leave well alone and just accept that old houses come with old floors — and then invest in some cosy slippers or mats in breathable, natural materials such as jute.
However, for most, a resolution more in keeping with our modern expectations of comfort is required.
If you are keen to retain the original floor finish, one solution is to carefully take up the tiles, stone or parquet before digging out the floor beneath to a level that will allow for insulation, a damp-proof membrane, concrete and, finally, the old floor covering.
Although this is a viable option, there are several issues that you will need to consider. Firstly, great care will need to be taken when removing the old covering. What’s more, having been laid down many years ago, the likelihood is that there is only one way it will all fit back together again, so keeping track of which parquet block went where is vital.
Secondly, the majority of modern insulation materials for solid floors rely
on an impervious dampproof membrane to keep the insulation dry. Using these can throw the moisture balance of materials, such as quarry tiles, brick, flagstones and even parquet, out of kilter. This means that damp could become an issue where it was before kept under control.
Insulating Old Floors
There is good news for owners of old homes with cold, hard floors, keen to maintain their period charm without compromising on comfort. There are now methods for insulating under these old floor coverings in ways that won’t interfere with their breathability. These new materials have the ability to absorb and emit moisture — something many modern systems fail to do. Plus, they can be laid successfully with underfloor heating.
One such product is Limecrete. “Limecrete floors provide a middle ground between modern concrete floors, with dampproof membranes and truly traditional vernacular floor construction,” explains historic building consultant Peter Hayes (archbuildingconsultancy.co.uk). “They are made up of aerated aggregate mixed with a hydraulic lime binder. The lack of fine material in the subfloor resists the passage of ground moisture through it. The ‘ honeycomb’ structure of floor aggregate also provides good insulation.
“Depending on the aggregate used, limecrete floors can be thinner than modern floor slabs, meaning removal of less soil from a site and reducing the potential for disruption or undermining of the wall’s substructure.
“Limecrete needs a permeable floor finish, such as flagstones. I wouldn’t recommend timber finishes or carpet.” Further information can be found at mikewye.co.uk.
Another product of interest for those considering this job is GLAPOR recycled foam glass from Ty Mwar (lime. org.uk).
“Adding insulation and a membrane beneath old floors is a disruptive job, but well worth it”
You should be aware that adding insulation and a membrane beneath old floors is a disruptive, yet worthwhile, job. The floor will need to be dug up to the required depth before the ground is levelled and compacted. A breathable membrane is then laid, before the insulating materials. If you are fitting underfloor heating, this will be done before the final flooring is laid.
Listed buildings will require consent for this job.
Repairing Timber Floors
In the case of timber floor structures, the most common underlying problems relate to rotten timber joists.
If only small areas of timber are damaged it is usually easy enough to repair them like-for-like, but if the entire area is badly damaged it is worth considering a complete replacement. This can be a DIY job, but otherwise a skilled joiner or floor specialist will be able to help.
An alternative to a timber replacement is a steel i-beam system, such as Fastslab from CDI (cdi-icm.co.uk). This is a steel web hybrid system that spans from wall to wall and won’t rot over time.
“Problems with damp can occur when people take up a timber floor and fill in the void below before then placing a concrete slab over the top,” explains CDI’S director Paul Larnach. “We replicate the existing timber floor joist system with Fastslab, maintaining the void to allow proper air flow.”
When it comes to the floor joists on the first floor, it pays to ensure that they are reinforced. (Plus, if you hope to install bathroom tiles, floors may need to ply-lined and an anti-fracture matting used.)
“A product such as Lewis Deck is perfect for reinforcing timber first floors, although it is used on ground floors too,” explains Paul. It is made up of steel dovetailed sheets, 16mm in height. These fit together over the existing or replacement joists, before concrete or a free-flowing screed is laid on top.