Joist and Floor Loading Questions Checklist

Note which way any floorboards run and where the lines of nails or screws fall, since the supporting timbers usually run across the boards rather than with them.

Board direction is the simplest clue an owner can record, and it usually tells a professional which way to look first without lifting anything.

Look at the floor from below wherever it is exposed, such as in a cellar, a garage or an unboarded roof space, and photograph what you can see there.

One exposed area often explains the rest of the building, and it is the only view that shows the timbers themselves rather than what covers them.

Note which walls the floor timbers appear to run into at each end, and whether those walls continue downwards through the storey below.

Bearings are where an engineer starts, and knowing whether the wall carries on downstairs decides how far the enquiry has to travel.

Note whether the ceiling below has been replaced, lowered or boarded over, and whether the floor above still appears to be the original one.

A replaced ceiling hides everything and often dates from work nobody recorded, so knowing it happened matters more than what it looks like.

Record what the floor is finished with and what you believe lies underneath, such as boards, sheets or a screed, and note how you know that.

The layers between the finish and the timbers affect what has to be lifted, and owners often know from earlier work what is down there.

Mark on a plan sketch the areas where you genuinely do not know what is underneath, and note any hatch, loose board or access panel that already exists.

An existing access point is worth a great deal on the day of a visit, and owners are usually the only people who remember one is there.

Write down exactly what you intend to place in the room and in which part of it, noting whether it would stand near a wall or out in the middle of the floor.

Position within a room is one of the first things asked about, and owners usually describe the item carefully and the location vaguely.

Note anything that holds water when it is in use, such as a bath, a tank or an aquarium, and whether it would stay full between uses.

Items that fill with water behave very differently in use from how they look when delivered, and that difference is easy to forget to mention.

Note whether a heavy item would be fixed in place or moved around, and whether it would ever be dragged across the floor when it is loaded.

Something that stays put and something that is regularly shifted raise different questions about both the structure and the finish.

Note whether a heavy finish such as stone or tile is intended across the whole room rather than in one area, and whether it would continue into adjoining spaces.

A finish covering an entire floor is a different proposition from a single heavy object, and the two are often discussed as though they were the same.

Record any stove, hearth, safe, tank or fixed appliance you are considering, including anything a supplier has already been asked to look at.

Suppliers frequently size and locate an appliance before anyone has looked at the floor, and reversing that order is much harder.

Ask the supplier of any heavy item what information about its weight in use the engineer will need, and pass that on unedited rather than summarising it.

Owner summaries of weight information are unreliable, and handing over the original document is both quicker and far more useful.

Supplier information describes the item and says nothing about your floor; only a qualified engineer can consider the two together.

Note whether the loft is boarded, who laid the boards as far as you know, and whether they sit directly on the timbers or on something raised above them.

Owner-laid boarding is extremely common and tells a professional a good deal about what has been happening up there over the years.

Describe what the loft holds at present in ordinary terms, such as how many boxes and cases, and say whether they sit over one spot or across the whole boarded area.

Concentrated storage in one place is a different observation from an even scatter, and only the owner can describe which it is.

Note whether the roof space has ever been used as a room by anyone, including informally as an office or a bedroom, and record what you were told about it.

Rooms created in roof spaces without records are common in older housing, and a buyer, lender or engineer will ask about it directly.

Whether a roof space may be used as a room is a matter for a qualified professional and the local building control body; confirm locally what applies.

Record anything visible on the ceiling below the loft, such as a line of cracking, nail heads showing through or a dip you can see across the light.

Ceilings show things long before floors do, and the view across a ceiling in low afternoon light reveals what a straight-on look never does.

Note whether the loft hatch or ladder was cut in later, what appears to have been cut to make room for it, and who carried that out if you know.

Hatches are frequently enlarged by owners, and what was cut to enlarge one is exactly what an engineer will want to look at.

Ask a qualified professional what would have to change for a roof space to hold more than it does, and what is different about using it as a room.

Boarding a loft does not make it suitable for storage or occupation; what a ceiling structure can carry is for a qualified engineer to establish.

Photograph any notch, hole or cut you can see where timbers are exposed, including a note of which room it is under and roughly whereabouts along the timber.

Location along the timber is the detail that matters and the detail that is always missing from a photograph taken without a note.

Note where pipes and cables must cross the floor timbers, such as under bathrooms, kitchens, radiators and anywhere a run passes from one room to the next.

Where services cross the timbers is where cutting happens, and you can predict most of those locations without lifting a single board.

List earlier work that would have involved lifting floors, such as a new bathroom, a rewire, replacement heating or underfloor pipework, and note roughly when.

The history of who has been under the floor tells an engineer where to look, and only the owner holds that history.

Note any hatch, trap or access panel cut into a floor by you or a previous owner, and photograph it open if you can lift it without damage.

An owner-formed opening is both a useful access point and a thing worth showing to a professional in its own right.

Note whether a chimney breast, hearth or fireplace has been taken out on any storey, and mark on your sketch where it used to be on each floor.

Anything removed from a chimney raises questions about what remains above it; ask a qualified engineer rather than assuming the matter was dealt with.

Keep your record of where services run somewhere it can be found by whoever next lifts a floor, including any photograph taken while boards were up.

Photographs taken while a floor was open are worth more than any later investigation, and they are usually lost soon after the work is finished.

Mark the existing stair opening on your sketch, note which way the floor timbers appear to run around it, and photograph the edge from below if you can.

The area around a stair opening is arranged differently from the rest of the floor, and it is often where a new opening is being considered.

Note any partition standing on the floor above, and whether a wall appears to continue directly beneath it on the storey below or stops short of it.

A wall standing on a floor rather than on a wall below is a common arrangement and a common subject of these conversations.

Note any wall on the storey below that you hope to remove, and mark on the floor above exactly where its line falls, using a doorway or window as a reference.

Never assume a wall below a floor can be taken out; a qualified engineer must establish what it does before removal is even planned.

Note where a bath, shower tray or heavy unit would sit in relation to the walls, since something against a wall and something in the middle are quite different.

This is the single detail owners leave out most often, and it changes the answer more than the item itself usually does.

Record any new opening being considered through the floor, such as for a stair, a duct, a lift or a double-height space, and where it would fall.

An opening through a floor affects the timbers around it as well as the ones removed, which is why its position needs fixing early.

Note fitted furniture, tanks or appliances that cannot easily be moved, since they determine what can be lifted and what will stay hidden.

Fitted units decide what a professional can actually see, and knowing that before the visit changes what the visit is expected to achieve.

Note where the floor moves when somebody walks across it, including anything that rattles, a door that swings, or glasses that ring on a nearby surface.

Owners describe this as bounce, and where it happens within a room is far more informative than the fact that it happens at all.

Record any slope by placing something round on the floor in several places and noting which way it rolls, then mark those directions on your sketch.

A rough consistent test across the whole floor is more useful than a single careful measurement in one corner.

Note where gaps have opened between the floor and the skirting, between boards, or where a floor finish has pulled away from a wall or a threshold.

Gaps at edges tend to appear gradually, and an owner is usually the only person who can say whether one is new or has always been there.

Record any cracked tile, split grout line or ceiling crack below that runs in a straight line, and photograph it with something in shot for scale of position.

A crack running in a line often follows something underneath, which is why the line matters more than the crack itself.

Note any door on that floor that catches or has been trimmed, when it started and whether it varies with the weather or the time of year.

Doors are sensitive and are usually adjusted without anyone noting when, so recalling when trimming happened is genuinely useful.

Describe the bounce, the slope and the cracking as things you have felt and seen, and stop short of saying what you think is under the floor causing them.

Owners who name a cause tend to get that cause examined, when the useful thing is an engineer arriving with no fixed idea about the floor.

Nothing an owner notices about a floor establishes whether anything is wrong; that is for a qualified structural engineer to consider.

Ask what would have to be lifted or opened up before the question can be answered, who would do that and what condition the room would be left in.

Lifting fixed floor finishes to expose timbers is work for qualified people; owners should not cut, prise or remove floor coverings in preparation.

Ask whether anything could be established from below through a ceiling access, a cellar or an adjoining space, before floors are opened from above.

Looking from underneath is often less disruptive, and it is worth asking whether it is possible before agreeing to lift a finished floor.

Ask which parts of the floor will not be seen at all, and ask for that to be written down alongside whatever findings you are given.

An area recorded as not seen has not been assessed, and must never be read later as an area found to be satisfactory.

Ask who is entitled to change the approach if the timbers under the boards do not match what the engineer expected, and how you would be told about it.

Discovering something unexpected mid-project is normal, and knowing in advance who decides keeps that discovery from stalling everything.

Ask what any conclusion is based on, whether anything was measured or calculated, and ask for that to be set out in writing rather than said at the door.

Something said at the door cannot be shown to a builder or a supplier later, and the difference between a spoken view and a written one is rarely spelled out.

Decide where the photographs, sketches and findings about the floor will be kept, and note that whoever next lifts a board will want exactly this file.

Sale enquiries and the next project both reach back for this material, long after everyone has stopped thinking about the floor.