Wrecked boards and badly cut joists

Joined
28 Nov 2010
Messages
373
Reaction score
7
Location
Edinburgh
Country
United Kingdom
Would like a bit advice please. In my circa 1890 flat I've discovered badly cut boards and joists. At the moment only really seen some of my 1m wide by 9m long hall. Obviously over the years boards been up and down and plumbing/heating installed etc. I'd hoped to sand floors but suspect thats out.

My boards are I think 27mm thick.

Are using decent quality new boards an idea if I wanted to try and stick with the idea of floor sanding? I don't really want to start fishing around for reclaimed floorboards though I suppose I can see better exactly how much I might need when I lift carpets for a proper look at whole areas.

Other idea is perhaps plywood on top of joists instead of the boards. I'd put laminate or engineered wood on top. Would it need to be 25mm or 18mm be ok if boards going on top?

I welcome any suggestions for trying to bridge at some joists or attach some supports to sides of joists in places.

Thanks
 
Sponsored Links
My boards are I think 27mm thick.

Are using decent quality new boards an idea if I wanted to try and stick with the idea of floor sanding? I don't really want to start fishing around for reclaimed floorboards though I suppose I can see better exactly how much I might need when I lift carpets for a proper look at whole areas.
New boards won't really look the same as 120 year old ones - different grain and far looser rings (because they are second growth and grown much faster - old boards generally have far tighter growth rings). If you want a sanded hallway it may be better to swap out the bad boards for ones culled from other (carpeted) rooms in the house, such as a bedroom or living room. Those boards could than be replaced with new boards which, being carpeted-over, would never be seen

Other idea is perhaps plywood on top of joists instead of the boards. I'd put laminate or engineered wood on top. Would it need to be 25mm or 18mm be ok if boards going on top
Ply-over with 9.5m hardwood ply and it will take most of the inconsistencies out. You will need to screw the plywood down on at the very least 150mm centres (or 153 screws per sheet) to get a consistent stable floor to work on. In really bad cases it may be necessary to used a self-levelling compound in addition to take-out dips

I welcome any suggestions for trying to bridge at some joists or attach some supports to sides of joists in places.
Not 100% sure what you mean, but if you have insufficiently supported plank ends it is relatively simple to screw 2 x 1in slate laths onto the sides of joists to give extra support to the plank ends.
 
Last edited by a moderator:
Thanks for your reply. What is a slate lath?

When I mentioned ply I mentioned thick because of wondering about replacing the all the bad floor boards with plywood straight onto joists. Some of my living room is actually patched with very large boards. There is actually ply down just now over boards elsewhere but I think it’s only 6mm.

Thanks for idea re taking from other rooms. Will bear it in mind.

Would ordering some new boards in the correct thickness be quite a good idea in a situation like this?
 
What is a slate lath?
Rough sawn 2 x 1in (44 x 22mm) softwood, often treated with preservative (and generally coloured green or brown). Sold by most timber yards and builders merchants. It is the cheapest material you can get to do this sort of repair task and if bought wet you can screw it directly without the need to pilot drill and countersink the holes first. 2 x 1in PSE (planed, square edged) softwood is available but costs more and often needs to be pilot drilled and countersunk - and all for something which will never be seen...

When I mentioned ply I mentioned thick because of wondering about replacing the all the bad floor boards with plywood straight onto joists.
Sorry - thought you were thinking in terms of adding a new engineered floor surface over the top of the existing floor. If using plywood to repair floors it will need to be cut to fit and ideally should be wider than a single plank width for strength. It will also be necessary to pack beneath the plywood repairs to get the surfaces level with the old floor - that, or overlay 18mm with on or more layers of thin plywood (4mm, 6mm 9.5mm, etc) to build the surface up

Would ordering some new boards in the correct thickness be quite a good idea in a situation like this?
It might be. A decent timber yard or a small joinery works would be where I'd start. It may be possible to obtain salvaged boards from an architectural salvage specialist (they would be either yellow pine or pitch pine in all probability) and have them machined to dimension (expensive). In all probability you'll need to rip saw the boards to width to fit the gaps and you'll probably lose the T&G detail as well
 
Last edited by a moderator:
Sponsored Links
Not much tile up here - mainly slates or cleaved stone
 
Thanks for replies

JobAndKnock, when I mentioned the thick ply I was thinking perhaps lifting the hall boards completely and using thick ply instead, not patching areas with it. Maybe easier said than done though. To do it well I guess also would really need skirtings etc removed
 
Maybe. The price and weight of plywood thicker than 18mm can be quite off-putting (18mm weighs about 45 to 50kg a sheet, 8 x 4ft, thicker stuff is proportionately heavier - or maybe I'm just getting old... ). Also ex-stock availability of ply above 22mm is not guaranteed. Remember, you will need some way to transport it as well as the tools to cut it down to size on site
 
I used 18mm ply, very pleased with it though you do need to nog (strut) all unsupported edges, even the long ones, if it is not T&G.

For a proper job you should take the skirtings off. If the room is big enough to take more than one piece across, you can lift and slide it under the skirting. You will also be able to lift it whole for future electrical or plumbing work without hacking it about. This is I think very valuable. Do this if your hall is more than 1220mm wide.

If you want, you can dye it (Colron or similar) and/or varnish it.

Some places like B&Q will cut it, but the bigger the pieces, the more rigid it will feel.

It is difficult to get 1220x2440 pieces upstairs, so I had mine cut to 1220x1220 for the bathroom, which are light enough to juggle with. The rest I ordered in whole sheets and had it delivered.

Some grades of construction ply are very rough and splintery, and not intended to be seen.
 
Last edited:
Hi Silver50,

I was in exactly the same position as you a few years ago (also in an old Edinburgh property).

My solution was to bridge the gap with 25mm plywood. Its strong enough so that the long edges do not need supported. I put together a cut-list, then had the timber merchant cut it and deliver it. I used three lengths for the approx 7m length of the hallway, making sure each corner at least was supported. Then I plyboarded over it all with 6mm plywood.

To get the 25mm ply level with the top of the existing floorboard I used plastic window/joinery packers. You can get bags of 1, 2, 3, 4, 5 and 6mm ones from screwfix. Or if you only need a handful I have loads of 1, 2, and 3mm ones (I bought three boxes of 1000 each. Only need a few hundred, but cheaper to buy in bulk than buy small bags of 1-6mm)

Not many suppliers keep 25mm in stock. The one I used has closed down now (was on Gorgie Road). You could try St Andrews timber now though.

Ian


full




full


full
 
Thanks Ian and thanks to John D for his reply above.

I’m about to check out those packers. Seems likely I’d need mostly 1-3mm. I could maybe PM you if I wanted some?

One of things that puts me off ply is maybe placing suitable packers but it’s orherwise a good plan. As you say it’s thick enough it shouldn’t flex if not perfectly supported. I was thinking of Thornbridge (now iona st), they could supply me some manageable sized cuts but indeed it in itself is pricey however I imagine cheaper than having new boards custom made.

I need to lift more of my carpet and 6mm ply along the length of the hall to better see what I’m dealing with. Hoping to do this next week.
 
If you're wanting decent 18mm ply, i found the stuff from builder depot is very nice finish and only 32kg per sheet. If you're around London. They also do a thicker sheet too.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Back
Top