Pilot holes for loft legs?

[chrishooper]

Paranoid DIY question here.

I'm putting an 18 mm chipboard loft deck on xl loft legs using 4 x 30 mm TX screws.

Do I need pilot holes? In my head the joists will split and my roof will collapse.

 

[Dereekoo]

Putting in pilot holes means less wood and less strength, putting in screws just pushes
the wood fibres to one side

 

[conny]

I x 2.5mm pilot hole for each screw is not going to remove enough wood to weaken the joists. It will make it easier for the screws to bite into the joists and lessens the risk of the screw 'falling over' as you try to drive it in.
Without pilot holes, the screw will 'push' some fibres to the side, as Dereekoo says, but in doing so it rips them apart from their corresponding fibres anyway. I would recommend pilot holes.

 

[JohnD]

Pilot holes will make the screws go in easier and straighter

But will take a little more time

 

[RandomGrinch]

I used TX screws on mine; no issues, no splitting, they went in beautifully.

 

[opps]

Putting in pilot holes means less wood and less strength, putting in screws just pushes
the wood fibres to one side

I do not upstand your reply.

A pilot hole clears the shank of the screw

I am gonna mark your post as being extraodinarily stupid .

You really are out of your depth

A nail that is pre-drilled will, potentially be far more secure than one hammered in with out drilling.

 

[hllns]

If it's the plastic square top loft legs it's unnecessary, you don't screw downwards parallel with the joist, you screw down perpendicular with the shoulder face of the loft leg which means the screws are going towards the centre on a slight tilt from each side.

I highly recommend sitting down somewhere comfortable to put at least a couple if not all of the screws into the legs rather than just taking boxes of legs and screws up into the loft, you're then ready to just drive the screws in.

I also don't regret getting a cheap impact impact driver from Aldi in advance of doing it, made it easy.

 

[^woody^]

Use a self-drilling screw such as Turbo Gold from Screwfix.

Or a twin-thread screw and put a bit of wax or soap on the thread to ease it in, as the existing loft timber may be a bit denser than we get nowadays.

 

[Dereekoo]

.

 

[Dereekoo]

I do not upstand your reply.

A pilot hole clears the shank of the screw

I am gonna mark your post as being extraodinarily stupid .

You really are out of your depth

A nail that is pre-drilled will, potentially be far more secure than one hammered in with out drilling.

-

 

[opps]

-

Sorry, my reply was excessively curt.

A correct size of pilot hole will provide a stronger fixing.

You do not want to push the grain apart because that means that only two sides of the screw thread are in contact with the timber. With a piloted hole the thread is in contact all of the way around.

Other times where pilots are essential include drilling in to end grain or near the end of a length of timer. Failure to pilot may result in the timber splitting. Additionally when drilling in to hardwoods. If you don't use a pilot, the screw may snap.

 

[Dereekoo]

Sorry, my reply was excessively curt. - No problem we get your type on the site now and again

Unfortunately you missed the whole point of what was said. The OP was concerned with the joists/roof collapsing although I assume he meant the joist/ceiling due to screwing into the joists. The actual strength of the fixing was not raised. So back to my tongue in cheek reply, I'll try and keep it simple for your benefit. Try and imagine 5 planks laid vertically against each other in a vertical direction, spanning an opening, carrying a load. Imagine that the planks are just man enough to carry the load. Now drill completely through one of the planks so in effect there are only four planks carrying the load and the actual structural area decreases by 20%, result - collapse. Now imagine driving a steel rod in between the planks so that they actually are displaced sideways at this point, but are not severed, so the structural area of the wood remains the same, result - the structural area remains the same and the structural stresses are diverted around the hole so no collapse Now extend your thoughts further and imagine that these 5 planks are in fact hundreds of wood fibres making up a single joist. At the end of the day in reality pilot holes or no pilot holes will make zilch difference to the load carrying capacity of the joists and hopefully you get where I was coming from.

 

[freddiemercurystwin]

Pilot holes, no pilot holes it won't make the slightest bit of difference to the strength of his loft floor, assuming he's not screwing screws in right on the edge of the joists, that would be a bit daft, load of hot air over nothing as usual.

 

[opps]

Unfortunately you missed the whole point of what was said. The OP was concerned with the joists/roof collapsing although I assume he meant the joist/ceiling due to screwing into the joists. The actual strength of the fixing was not raised. So back to my tongue in cheek reply, I'll try and keep it simple for your benefit. Try and imagine 5 planks laid vertically against each other in a vertical direction, spanning an opening, carrying a load. Imagine that the planks are just man enough to carry the load. Now drill completely through one of the planks so in effect there are only four planks carrying the load and the actual structural area decreases by 20%, result - collapse. Now imagine driving a steel rod in between the planks so that they actually are displaced sideways at this point, but are not severed, so the structural area of the wood remains the same, result - the structural area remains the same and the structural stresses are diverted around the hole so no collapse Now extend your thoughts further and imagine that these 5 planks are in fact hundreds of wood fibres making up a single joist. At the end of the day in reality pilot holes or no pilot holes will make zilch difference to the load carrying capacity of the joists and hopefully you get where I was coming from.

Wow... I apologised for being overly curt, your response is "No problem we get your type on the site now and again"

You posted factually incorrect advice, I (impolitely) corrected you, but hey, why not double down...

I agree that in the OP's case a pilot hole might not have been required, but you are absolutely wrong when you suggested that driving in a screw into timber without a pilot hole is better than drilling a pilot hole.

Apropos working with timber, I think it is safe to say that @JobAndKnock is the most informed member on this site. I would be shocked if he agreed with your claim that driving in regular screws, without pre-drilling results in a stronger fixing.

 

[Dereekoo]

Wow... I apologised

Never apologise (thats twice), its a sign of weakness (John Wayne - She Wore a Yellow Ribbon)

You posted factually incorrect advice,

No advice posted just offered up sound structural information which was

Putting in pilot holes means less wood and less strength - are you saying thats not correct (even though its a nano of a N/mm2)?? If so it will make all the posters who query the location/number/size of holes in or to be put in floor joists sleep a whole lot better.

Putting in screws just pushes the wood fibres to one side - are you saying that when you screw a screw in the wood fibres don't get pushed to one side (as a nail would when driven in)? And if not the where do they go?

I (impolitely) corrected you,

You did not correct me, impolitely or not, as I have tried to explain to you (to no avail) , my comments were directed towards joist strength whilst you went off on a tangent on about fixing strength enhanced (or not) by having pilot holes with the need at end grains, to stop timber splitting and hardwood and broken screws thrown in for good measure

I realise that it can sometimes be hard to grasp adjacent but slightly (thats being kind) different principles but please try

At the end of the day in reality pilot holes or no pilot holes will make zilch difference to the load carrying capacity of the joists and hopefully you get where I was coming from.

I agree that in the OP's case a pilot hole might not have been required,

Its good that you agree with me

I think it is safe to say that @JobAndKnock is the most informed member on this site. I would be shocked if he agreed with your claim that driving in regular screws, without pre-drilling results in a stronger fixing.

I cannot comment on the 1st part of the statement and others may or may not agree but I would also be shocked if he agreed with my alleged claim as said claim does not exist except in your head and it would then make him appear as confused as you thus, in my humble opinion, disproving the 1st part of your statement.