Suspended Timber Floor

[Deleted member 174758]

In that case carry on as you were . The concern I had about the side joist being fixed to the wall was mainly that noise transmission would be increased over a "hanging" joist, but also that it gives more opportunity for the spread of damp or rot (which, granted, are more of a listed building issue). And on that point, when you install solid strutting it should not fill the gap between the wall and the first joist, for the above reasons of noise and rot

 

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Infilled the right hand side as below.

How tight should the bolts be into the chem fixing? They have been done up tight but could be cranked a little further. Guessing when it's all fixed together the bolts don't actually add much to the party in terms of pulling off the wall?

 

[Deleted member 174758]

I don't know how you've done your anchors, so I'll put down the most detailed esplanation I camn of how I use them. Bear in mind that a lot of the resins I put in are inmto ropey Victorian or Georgian brickwork where we might only get one decent fix for every three holes - in modern masonry you should get almost every one spot on. I've included a fault finder below that

The way you I resin anchors is to drill the holes (2mm bigger than the stud, no more), blow out, brush out or vacuum out any drilling debris, then inject the resin - starting with the mixer nozzle full in gto the shouldet of the nozzle pumping and withdrawing the gun gently (the idea is to almost completely fill the hole but not drop any resin into voids or cavities - with the guns we use that is about 3 to 5 pumps) then slowly insert the threaded stud V-shaped end first whilst turning slowly (you are effectively screwing the stud into the resin, making sure that the threads get a good purchase on the resin). Put the washer(s) and nuts on, but leave everything loose until the resin sets hard (20 to 60 minutes depending on temperature and resin type). This is another reason why I put the temporary support blocks on the wall and why I often use a few brown plugs and 5 x 100 mm screws to hold the ledger in place until the resin sets. Once the resin has set, tighten the nuts to hand tight, no more - don't tighten until the resin is fully cured (often 12 to 24 hours, especially in winter ). Some stud suppliers, such as Hilti, machine a square on the ends of their studs so that you can do the first tightening before the resin is cured by holding onto the stud with an OE wrench. when the resin has fully cutred revisit the nuts and fully tighten with a wrench or ratchet - they should all tighten fully, but invariably some won't (at least in old brickwork or soft masonry). How many do you have and how many are suspect?

Some reasons why studs won't tighten (not comprehensive, but everything I can think of at the moment):

1. Hole still contains debris (not cleaned out thoroughly) leading to poor adhesion between resin and masonry
2. Hole drilled too large (needs more resin)
3. Insufficient resin injected
4. Stud threads not bedded into resin (pushed in as opposed to screwed in)
5. Resin pushed out of hole and into a void cavity because stud insertion too vigorous (go slower and screew in stud)
6. Hole drilled into mortar or invisible void in masonry
7. Attempt to fully tighten before the resin is completely cured

BTW - it's looking good

 

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Thanks. 14 along the rear wall from memory. I think only 1 has failed. Its in new blockwork so seems to have worked a treat. When I tighten the following day how mad should I go on the wrench? Tight then another full turn?

 

[Deleted member 174758]

1 fail is well within the bounds, especially as you seem to have put them in on fairly close centres.

Hand tight plus one turn should do the trick.

I know the description of the process I posted earlier may seem a bit OCD - as indeed it is - but successful resin anchor installation really does depend on being very thorough. Slap-dash installation leadscto many more failures

 

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I have an internal wall I need to hang joists from. Does the ledger board need to be fixed right back to this wall or can it be set off the wall using timber packers behind each bolt point to allow services to pass through?

 

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If a joist is sitting slightly low at the hanger end is it OK to sit some steel shims in the base of the hanger to sit the joist up?

 

[Deleted member 174758]

Does the ledger board need to be fixed right back to this wall or can it be set off the wall using timber packers behind each bolt point to allow services to pass through?

Ideally fix directly to the wall and make as long as possible. For internal walls your ledger doesn't need to be treated timber, but if the ledger is below ground level a DPM behind it is still a good idea. There is no reason why you can't notch over wiring, CH pipework, etc

If a joist is sitting slightly low at the hanger end is it OK to sit some steel shims in the base of the hanger to sit the joist up?

It isn't ideal and generally isn't acceptable to the BCO (although they will normally accept small notches), but so long as you drill and countersink it and screw it to the underside of the joist (so that it can't ever drop or be pushed out) I can't see the problem

 

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Is there an easy way or removing the nails? If so I can remove the 2 hangers raise up and re fix. I had mechanically fixed the shims so they could never move but if it is a risk for the sake of 2 hangers it may be best to remove and replace? What do you think

 

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I have finished the front half and now on the back which is going far quicker as I have learn the process. Where the joists meet in the centre can they be screwed as well as installing a solid timber brace between them?

 

[Deleted member 174758]

Yes, definitely screw together. lseo fix tpo the bearer beneath them (two skewed screws)

 

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I had planned on putting a noggin/solid brace at this point but thinking about it today where the joists meet is the transition from the original house to the extention. I had wanted this left open to allow some nice airflow between the 2 areas. Is it OK to set the brace off to one side or the other or to use a smaller timber (4x2) to brace?

 

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The large air gap shown in the previous photos is to either side of the main area. This will feed a lot of air in but in the main area the air gaps are provided by gaps between the blocks under the supporting plate and between the joists (as below). Will this give enough airflow if i fully brace between the joists at te wal plate.