Half lap joint or t&g

[jonifife]

We have sourced some floor boards and would like some advice on jointing if anyone has any exprerience...I have reposted here as is related to carpentry as much as flooring

T&G is the normal option but was thinking would like to half lap as would like to express the joint and will also be easier if i need to get at cables below.

The boards are ex 150x25 dougy fir fitted direct to joists spaced at between 300-400 ctrs

Can't seem to find much on the net- Is a half lap doable and can anyone recommend sizes for a profile?

Cheers

J

Read more: //www.diynot.com/forums/floors...d-joints-half-lap-or-tg.293384/#ixzz1ZvTpRLGK

 

[ladylola]

Doable but in all honesty you won't really be gaining anything. You would be better off putting in a loose tongue or even biscuits at a push. I've also seen metal dowels used but very very rarely the joint you are talking about.
Not quite sure what you mean by being able to express the joint, although you could always use the rebate or half lap for the access boards.

 

[jonifife]

Our old house had square edged boards and we quite liked the 'penny joint' effect.
We can't have square edge because of fire regs. Was thinking ahealf lap would allow for a mm or 2 gap between boards rather than t&g which is a bit more snug.

If I go t&g, How does the loose tongue thing work?

Cheers

J

 

[Jasonb]

Use T&G with a longer tongue than the groove depth and that way you will get your open joint.

For loose tongue just cut a groove in both edges and then use strips of ply as tongues, again if the ply is 2mm wider than depth of the two grooves you will get your gap.

Check the moisture content of your timber, the reason the old square edge boards had a gap was that they dried out over time, not helped by central heating, they would have been butted tight when originally fitted. If your timber dries out you may end up with a bigger gap than expected.

J

 

[jonifife]

Thanks, makes sense t&g it is - the se boards were in our previous house and just liked the gappy effect

we will be leaving the timber to acclimatise for a week or 2 and they are also being kiln dried so hopefully they wont move about

Sorry if i'm being a bit dense does the loose tongue go for a full length board around where i need access or just put shorter ones in.
Is the idea to cut through the ply when access is neededand replace?

The more I can get right now at time of order will save less hastle when laying I hope

Cheers

 

[JohnD]

if you want to be able to lift them out to get at pipes and cables, you could cut off the lower tongie of the grooved edge (IYSWIM)

you might like to fix the liftable boards to a noggin, or battens so you can lift out the hatch in one piece. You won't be able to secret nail though.

 

[jonifife]

Cheers John D - got the lower tongue bit doesn't that leave me with something like a half lap