Suspended Timber Floors in Surrey Hills: What to Check First

A lot of Surrey Hills houses sit on stumps, with the floor framed over a crawl space instead of a concrete slab. You can lay a new timber floor over that kind of structure without trouble, once you have checked the condition of the old floor. Bounce, squeaks, a slope towards one wall, blocked vents and damp soil underneath all need attention before the new boards arrive. This guide walks through what to look for yourself and what our installers check at the measure.

How a suspended floor is put together

Most weatherboard and interwar brick houses in Surrey Hills were built the same basic way. Stumps, originally timber and now often replaced with concrete, sit in the ground in rows. Bearers run across the tops of the stumps. Joists sit on the bearers at closer spacings, and the floorboards are nailed across the joists. Later extensions may be framed the same way, or built on a slab.

Each layer can cause its own problem. A sunken stump makes the floor above it dip. A joist that has sagged or split gives you a springy patch. A board that has lost its nails squeaks. Air moving through the gap underneath keeps the timber dry, but it also brings cold air in through gaps in the old boards. Knowing which layer is at fault tells you who needs to fix it and in what order.

Checks you can do yourself

You can learn a lot without going under the house. Spend ten minutes walking the rooms you want to re-floor and note down what you find.

1. Bounce. Walk heavily across each room, and stand in the middle. If the china cabinet rattles or you feel the floor give, note where.
2. Squeaks. Walk slowly along the length of the boards. Squeaks usually come from loose boards rubbing on nails or on each other.
3. Slope. Put a marble or a round pencil on the floor in a few places. If it always rolls towards the same wall, the floor has a slope. If it rolls into the middle of the room, something underneath has dropped.
4. Doors and windows. Doors that have started to stick or swing open on their own, and cracks opening in plaster above doorways, often mean stumps have moved.
5. Vents. Walk around the outside of the house and look at the vents in the brick base or the weatherboards near the ground. Note any that are blocked by garden beds, paving or a later deck.
6. Heating registers. Count the ducted heating vents in the floor of each room and note where they are.

None of these rule out a new floor. They tell us what the preparation will involve, and they help you ask better questions when you get quotes.

What the symptoms usually mean

What you notice	Likely cause	What happens before new boards
Squeaks along the boards	Loose boards or popped nails	Boards are fixed down to the joists
A springy patch in one area	A sagging or damaged joist, or a missing stump under it	Checked from underneath; a carpenter or restumper may need to add support
Even slope towards one wall	The house has settled unevenly over decades	Often floored over if the slope is gentle; the new floor follows it
Dip in the middle of a room, sticking doors	Stumps that have sunk or failed	Restumping or packing by a restumper or builder first
Cupped boards with raised edges	Moisture from below, often poor ventilation	Find the moisture source, then plane or sand the boards flat
Musty smell or soft timber near outside walls	Damp, rot or insect damage	Inspection and repair before any flooring work

Restumping isn’t part of our work as flooring installers. If the problem is in the stumps or the frame, we will explain what we found and recommend having it fixed first. Laying a new floor over a structure that is still moving can mean paying twice.

Ventilation and damp under the house

A suspended floor relies on air moving through the space underneath. That airflow carries away the moisture that rises from the soil. When vents get blocked, the air goes still and damp builds up. Over time that shows as cupped boards, a musty smell in the back rooms, and in worse cases rot in the bearers and joists.

Older houses often lose vents over the years. A garden bed gets built up against the house, a concrete path is poured over the lowest row of vents, or a deck is built across the back of the house with no gap under it. We recommend clearing what you can before the new floor goes in. A new engineered floor sitting on top of a damp subfloor will take on that moisture too.

At the measure we look for signs of moisture in the existing boards, such as cupping, staining and soft spots. Boards that show damp in one corner are a clue to look outside that wall for a leaking downpipe, a garden tap or a blocked vent.

Draughts and ducted heating registers

Old boards shrink over the decades and open up gaps, and cold air from under the house comes straight up through them. A new engineered floor laid over the top covers those gaps, which helps. Our Surrey Hills flooring page covers warmth and insulation in more detail.

Ducted heating is easy to overlook. Most houses of this age have had gas ducted heating added, with registers cut into the floor in each room. When a new floor goes over the old one, each opening has to be cut through the new boards so the duct lines up underneath. Re-cutting vents isn’t a service we currently offer, so please plan this with your heating technician; we mark where the registers are at the measure. Because the floor is now higher, the old vent covers may sit proud or loose. Plan for new covers and decide whether you want metal ones or covers that match the floor. Also check that none of the registers sit where a board join or a doorway trim will land, since moving a duct slightly is easier before the floor goes down.

What our installers check at the measure

When we visit a house on stumps, the measure takes a little longer than on a slab, because we are checking the structure as well as the rooms. We usually check:

• How firmly the old boards are fixed, and whether any are soft, cracked or cupped.
• Flatness, using a long straight edge across the rooms and along the hallway.
• Bounce and give, especially in the middle of large rooms and near old fireplaces that have been removed.
• Signs of moisture in the old boards: cupping, stains and soft spots.
• Access under the house, if there is a manhole or crawl space, to look at the stumps and the ventilation.
• Floor heights at doorways, the back door and any step down to an extension on a slab.
• Where the heating registers are, and how the new floor meets them.

From that we decide whether the new boards go over the old floor or the old floor comes up, and what fixing and planing is needed first. All of it shows on the quote as separate lines. Our floor removal and subfloor page explains the preparation work in more detail.

Choosing boards for a floor on stumps

Once the structure is sound, most engineered boards work well over a suspended floor. Our engineered oak is 15 mm thick, and our Australian hardwood boards, such as Blackbutt matte brushed, are 14 mm, all tongue and groove. Both add less height than a traditional solid board, which helps at the back door and the bottom stair.

A house on stumps moves more through the seasons than a brick house on a slab, so the expansion gap around the edges of each room matters. So does the join where an old house on stumps meets a newer extension on a slab. The two parts move differently, and the floor needs room to move at that line. If you are comparing engineered boards with full solid ones for an older house, our guide to engineered vs solid timber flooring covers the trade-offs.

Your next step

We suggest doing the ten-minute walk-through above and write down what you find. Then book a free measure and quote, and tell us when you book that the house is on stumps and whether there is a manhole. We will check the structure along with the rooms. You’re also welcome to visit the showroom at 2/1386 Toorak Road, Camberwell, next door to Surrey Hills, or call 1300 690 160.