Skirt fixing screws and countersink

[Mattatooi]

Hi I am about to install skirting. I have MDF skirting, 120mm H, 18mm deep. All skirting is being fixed to solid wall. I want to screw these in. I just am not sure on some sizes. Bit of a newbie to screw sizing.

I presume I should use 6mm raw plugs, with 6mm drill bit? When putting screws in, what size of screw should I be using length wise and what size of countersink bit should I use to make the screw flush in. What does it mean on the screws if it is a #4 / #6 etc screw size? I need to buy these bits, have a local DIY merchant handy but also screwfix is pretty close too.

Also, what is best to fill over the screw heads. I will be painting the primed MDF skirt once installed. Decorators caulk?

Thanks

 

[Jackrae]

Hash4 and 6 were the old numbering size for screws but does not relate directly to the actual screw dimension in mm. These days it's normal to size wood screws by their diameter in mm eg 3.5mm, 4mm, 4.5mm, etc
I'd base screw length on 25mm into the brickwork plus the thickness of your skirting. So, if the skirting is 15mm thick then you'll need screws at least 40mm long. I'd say 4 x 40

You will not be able to countersink for a flush finish. The technique is to over-sink slightly and then use filler to produce a flush finish. A countersink about 10mm wide should do you

Is your skirting primed with paint or is it that horrible plastic coated stuff that the B&Q sell. If the plastic coated then you'll have a job on your hands trying to hide any screw-holes you make. Your best bet for stuff like that is to forget nails or screws and simply glue it onto the wall with a filler glue such as "Sticks like Sh*t"

If simply primer painted and you really do want to use screws then Ronseal 2-part epoxy filler is the best to use. It sands down perfectly and doesn't crack or shrink (like some of the plaster based fillers do). Mind you it starts to cure pretty fast so you get less than a minute to use what you mix.

 

[Burnerman]

If you get a good fixing into the brickwork, then consider screws 40 or 45mm long, and 4mm diameter (thats the screw shank size).
Fill the CSK with Polyfilla or similar - decorators caulk doesn't sand well.....any countersink bit which is slightly bigger than the screw head is fine.
John

 

[Mattatooi]

Thanks.

No its not the cheap B+Q stuff. It is primed with paint. Got from local timber merchant.

I would use adhesive but I have some long sections (4.4m) where the wall is not the straightest so I do feel I would need screws to hold firmly in place. I will probably stick some of the smaller sections in.

I understand it will not be flush as I would need to allow space for the filler to go on top. You mention the filler has a very fast curing time. Is there anything else a bit easier to work with? Does basic wood filler just not work? Does it not stick to the screw or something?

And just one other thing, are standard screws fine or do I need brass?

If screw is 4mm, then I need brown rawl plugs? and a 10mm countersink bit should do job.

Great thanks.

 

[Jackrae]

The epoxy filler really is quite easy to use, it's just that you need to work with small batches, filling holes proud then sanding off after fully cured (30 minutes)

I use a 1" paint scraper as an application tool simply wiping a knob of filler over the hole. It matters not if you don't get it properly filled first time. Just wait until cured, sand off the excess then apply some more to the low spots, cure and sand again.

As you're filling the screws, you don't need brass ones. Make sure you use pozidrive ones and a good quality screw driver or bits (that's one tool where quality counts) Cheap ones lose their working edges very quickly and soon become useless. I find a battery power drill a real boom to fixing screws

You will of course need to drill through the skirting into the wall so's holes all line up correctly.

 

[Mattatooi]

Yeah got a cordless and a corded. Just looking into it, red raw plugs do 3.5-5mm so I guess I need these, 6mm masonry bit and wooden, and 4x40mm screws, and can only see a 12mm countersink bit in local merchant site, so this should do the trick.

Thanks all, will go get in morning!

 

[Deleted member 174758]

red raw plugs do 3.5-5mm so I guess I need these, 6mm masonry bit

Normally it's 5.5mm for red plugs and 7mm for brown plugs - hole size based on the outside diameter of the plug. If you are going into soft block then reduce by 0.5mm or 1mm. You may find that 6mm holes don't give you sufficient grip

BTW it's a "Rawl" plug, not a raw plug. Rawl is the name of the original British manufacture of masonery plugs (bit like Hoover....)

 

[Burnerman]

Use 6mm plugs with a 6mm masonry bit, Matta.
John

 

[gregers]

i always use a 6mm bit when im doing skirts as the cheap red plugs that you get now tend to bend very easily when your hammering them through the timber/mdf,if your using a 2" 8 screw you really shouldnt need to counter sink as when your screwing in it should bite and pull itself in.

 

[Argyll]

I always use 5mm x 50mm screws and red rawl plugs. Some might say that's overkill but I've seen a few skirting boards pop out over the years.

Your best to line up your skirting boards and drill (6mm) straight through the skirting board and wall at the same time. Put your screw into the rawl plug by hand and give it half a turn just enough so the rawl plug sits on the screw without falling off. Offer up the rawl plug and screw to the hole in the skirting board and gently hammer in until about 30mm of the screw is showing. Then screw in slowly using a drill driver until you can feel the screw bite. As someone suggested drill a bit further in to the MDF so the head of the screw is a couple of mm into the mdf. Do this every couple of feet and you'll have it up in no time. It's definitely the fastest way. Use two part filler as someone else suggested.

Do you know how to mitre your internal corners?

 

[Mattatooi]

Will actually drill holes in skirt first then place skirt in place and drill into wall with masonry bit.

Would have thought countersink is neater, and means less chance of making any damage when screw is driving in, so will be sticking with that.

I am scribing my internals, mitre for externals.

 

[Argyll]

Would have thought countersink is neater, and means less chance of making any damage when screw is driving in, so will be sticking with that.

You're giving yourself extra unnecessary work but it's your call.

 

[Argyll]

You said in your first post you'll be countersinking to make the screw flush. The whole idea of countersinking is not to make the screw flush in order to fill it to hide the screw.

 

[Mattatooi]

Just badly worded. I meant to get the screw in so it can be filled to be flush finish.