Wall screws

[minniecat2406]

I have a 7.8kg shelving unit to put up. Annoyingly it didn't come with fixtures so what length screw do you think I'd need? There are 4 screws needed. Thank you!

What is the wall made of? (this is important)

I'm not sure to be honest. It's an internal wall of that makes any difference?

You need to establish whether the wall is a plasterboard stud wall, a solid brick wall or a brick wall that has a plasterboard facing. The shelving unit is quite heavy so will need proper support.

If it is plasterboard then you would be best off with 'butterfly' rawl plugs. If a brick wall, with or without plasterboard then I would suggest getting some 'heavy duty' fixings - places like b&q and Homebase do packs with the rawl plugs and screws together.

To work out what sort of wall it is, try tapping it. If it sounds hollow all over it is likely to be plasterboard. If it doesn't sound hollow it's brick. If it sounds hollow in some places but not all then it is likely to be 'dot and dab' plasterboard.

How old is the house?

Is it a brick house?

Awesome, thanks so much for the advice. It's a Victorian brick terrace so I'll see if I can work out what the wall is made of and take a trip to B&Q

If it's a Victorian terrace it probably has thick lime plaster on the walls. The external walls and the party walls will be brick. Some internal partition walls may be timber stud work with a plaster skin.

Your screws will have to go through the plaster to be supported by the wall behind. In brick you will need about two inches plus the thickness of whatever you are fixing to it, with plasplugs tapped at least an inch into the brick. Don't try to put a load on the plaster as it will fall off.

On hollow walls you will have to fix into the studs (no plasplug required) which might be in the region of two foot apart.

Watch out for pipes and cables... on the side you're drilling and the opposite side if it's a partition wall. Google safe zones for a starting point.