drill bit/lintal problem

[chrisray]

I have tried the search box, though havn't seen anyone with the same problem as I.

I have a large bay window, 3m wide. Over the bay window is what I've been told is a Lintal. There's plaster roughly 10mm into the wall, then as far as I know its concrete but feels more like drilling into stones than anything. It's a hit and miss, some of the lintal seems to be solid when I knock on it, other bits seem to be only plaster or hollow feeling.

Curtain rail is similiar to this

http://www.homebase.co.uk/webapp/wc...001&langId=-1&catalogId=5201&productId=264715

It's got three fixings.

First time it went up, fell down shortly after putting it up using plastic wall plugs and the correct screws.

The second, I got some blocks of 12mm timber and although it look glastly, it worked. The timber was mounted to the wall and the curtain fixings onto the timber. You guessed it, the timber broke and then the curtain rail fell down again.

My solution to this seemed simple. I could get a large timber board, fix it to the wall and then fix the curtain rail to this. Fixing the problem, as the board would even out the weight of the rail, and the wood would be stiffer (hopefully not work loose like the plaster seemed to) and break. Though the board I have is 10mm thick and I don't think the short screws would hold the weight of the rail.

OK, finally.. use heavier weight wall plugs to begin with.. seriously don't know why I didn't do this to begin with. Though, I have to drill into the lintal, 40mm min. This is the problem, my drill is a bosch 550w, it has the power, but stops drilling roughly 30mm into the lintal, though on some of the lintal I've managed to drill 45mm into it, then can't drill anymore. I've used an 8mm HSS drill bit and an 8mm masonary one, though they were from a cheap set.

Can someone recommend me some drill bits to buy, which will work.

Or recommend me a solution to fixing a curtain rail up on a lintal?

 

[Belle427]

depends on if its a concrete lintel or a metal rsj,you could try a smaller hss bit to start off with to give you a pilot hole,then the larger bit,not worth paying a fortune for drills though as you may blunt them if you hit concrete anyway

 

[^woody^]

It seems that you are not using an SDS drill?

Your drill is going through the plaster and outer soft concrete and then stopping at the hard stuff.

The advice to try a smaller bit first is good, and press on it to help the hammer. Else borrow or hire an SDS drill and this will fly through

 

[JohnD]

If, after the plaster, it seems to be concrete (not metal) then I wonder if you are in a reinforced concrete lintel, which has steel bars in it. the masonry drill will not be much good at steel. An HSS drill will do it, but will go blunt as soon as it touches concrete. If you are not equipped to sharpen drills you may get through several.

Is there anything you can do to detect whether the lintel is reinforced concrete or steel? e.g. chip off some of the plaster where it will not show later, and have a squint at it? A reinforced lintel will be smooth, light grey concrete, and if you drill an inch higher or lower, you will probably miss the steel reinforcing bar. A steel lintel may have expanded metal mesh round it to give the plaster a grip.

If it is concrete, then a good hammer drill with a sharp new masonry bit will do it. There are some cheap SDS drill about that will be OK for light use (but would not last long with a professional).

 

[chrisray]

Thanks for the advice!

I had no idea that it could be re-inforced concrete, with steel in? I have no idea. Though because its been so tuff to drill into I'm expecting thats the problem. I will fetch a torch and look, as I can't chip away at the wall anymore.. there's enough holes there already!

As far as I know its not a SDS drill. Just a normal Hammer drill/550W.

I know that perfectly in the middle of the lintel, the wall seems light and weak, almost like when you knock onto a plasterboard. However moving left or right from the centre, its solid wall. Its a bit hit and miss.

Thanks again.

 

[Static]

Get/borrow an SDS drill with concrete/masonry bit, it will go through the concrete like butter. Hammer drills will just melt the drill bits.