# Forum Home Renovation Rendering  Drilling into cement render

## Novice_79

Hi all 
First time poster and first time home renovator so please forgive any 'dumb' questions. 
I'm trying to install a set of timber vanitian blinds however my walls are cement render and don't have any wooden architraves into which I can drill a hole to install the screws that hold the wall mount in place. 
Because of this (correct me if I'm wrong), I have to drill a larger hole than I would if it was wood and plug that hole with those coloured 'screw plugs' (not sure of their exact title). This will then enable me to screw the wall mount for the blinds into the cement rendered wall snugly. (I'm using a 6mm masonry drill bit to drill these holes into the wall). 
The problem is however, the hole created by the 6mm drill seems to be too large. I've marked in pencil on the wall where to drill each hole (as per the wall bracket) and I've drilled one hole to test it, but there doesn't seem to be much room to drill the other holes (due to the size of the hole created by the 6mm masonry drill!) 
I need to drill 4 holes in a pattern like this: 
*          *   
*           * 
so as you can see, any large hole impeeds on my ability to drill the other holes due to their size. 
Can anyone recommend any tips for drilling into cement render generally or specifically for this situation? 
I'm at a loss what step to take next before I go drilling any more holes! 
Thanks all in advance. 
Novice.

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## ozwinner

First up, welcome to the nut house. 
How far apart are the holes to be horizontally? 
There is a product put out by Ramset that is an epoxy, its just a 2 part glue, but boy is it hard.
Anyway, maybe drill out around where you have to and glue in some wall plugs with the glue. 
Al  :Smilie:

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## Tommy

You may have to decide if your blind really needs to have four screws to hold it up ? .Sometimes brackets like this have extra holes so you can decide which ones you will use that best suits the job at hand.It also gives you the option of staggering the screws so you dont split the timber.This is more than likely the case..If you definately need to use the four holes the other option is to drill a elongated hole into which you hammer in a piece of timber that is just ever so slightly bigger than the hole but still small enough to be covered by your bracket.You can then screw into to timber.Hope this helps . :Biggrin:

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## bricks

If you've got the big 400 by 200 mm bricks chances are it is something like a bessa block, I find older ones tend to be very crumbly, try drilling with a smaller drill bit and useing the same size plugs, also take the hammer action off the drill- this can make it jump around abit which makes your hole too big.  
Another thing i've found is that the deeper the hole- the better the brick holds up- in any case you want to go straight through the render layer into solid brick. I have found sometimes drilling a hole which is way to deep and useing an extra long plug while seeming like overkill, actually works quite well. 
As tommy said - using only two holes may be an option. If i did that id get longer chunkier screws to replace the (usually) short skinny ones they give you in those kits. 
Perhaps two screws and a bit of construction glue on the back to stop the braket working loose. 
If the star plug your putting in the wall doesn't go in all the way- dont stress, just use a sharp knife to cut it off flush with the wall. As long as there is enough to grab the screw you should be ok

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## Barry_White

Hi Novice 
As an installer of venetian blinds for several years I can guarantee you will only need two screws in each bracket. What you have to remember is by your sketch of the bracket the screws will be in shear rather than tension so by virtue of the fact the weight of the blind would have to break the screws and that would never happen. 
Just as a tip I would drill a deeper hole past the depth of the render and push the plug to the bottom of the hole and use a longer screw. With a 6mm plug you need to use a #8 screw

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## Novice_79

Thanks for the advice guys, really appreciate it. 
To answer some questions, ozwinner, the holes horizontally are 7mm apart. Now that I think about that, it really wasn't smart getting a 6mm drill bit was it?  :Doh:  
Tommy and bricks, I'm not sure whether all 4 holes are required. The blinds are pretty bloody heavy though. I wonder if I just used 2 diagonal holes and a bit of construction glue to hold the bracket onto the wall whether that will be enough. This construction glue, is there anything in particular you can recommend and how strong (generally) is it? 
As for the hole itself and what to put in it (ie a tiny piece of timber or the star plug), I forgot to mention my drill bit is only letting me into the wall about 10mm whereas the screw that came packaged with the blinds are a decent 30mm long (long screws as you recommend bricks). I don't know why, but it seems the brick or concrete (whatever it is) 10mm in, is tougher than the outer layers. 
It is an older building (unit) that I live in and is quite crumbly. 
Out of curiousity, (and to satisfy the other halves stress levels!) if I was to call in a tradesman, who would be the best bet? A handyman? Brickie? I have strong fears about f***king this wall up.  :No:

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## Novice_79

> Hi Novice 
> As an installer of venetian blinds for several years I can guarantee you will only need two screws in each bracket. What you have to remember is by your sketch of the bracket the screws will be in shear rather than tension so by virtue of the fact the weight of the blind would have to break the screws and that would never happen. 
> Just as a tip I would drill a deeper hole past the depth of the render and push the plug to the bottom of the hole and use a longer screw. With a 6mm plug you need to use a #8 screw

  You don't do house calls by any chance do you Barry?!  :Biggrin:  Or can recommend anyone that installs blinds already purchased by the customer? 
As per my last post, for some reason I can't get too far into the wall. The screws that are included with the blinds, I'm not too sure what no. they are. I think I might need to visit the hardware shop and get them to identify what size screws these babies are.

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## Barry_White

> You don't do house calls by any chance do you Barry?!  Or can recommend anyone that installs blinds already purchased by the customer? 
> As per my last post, for some reason I can't get too far into the wall. The screws that are included with the blinds, I'm not too sure what no. they are. I think I might need to visit the hardware shop and get them to identify what size screws these babies are.

  Sorry novice you are a bit far away to do a house call. Where did you buy the blinds from. Maybe they have an installation service. 
#8 screw is the gauge of the screw, you would probably need them to be about 1-1/2" long or 40mm. 
As to construction adhesive liquid nails or maxbond will do the job but you really need to drill into the hard brick to get the holes deep enough.  
Do you have a percussion drill or just a normal drill and you have to use a masonary drill bit.

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## Novice_79

> Sorry novice you are a bit far away to do a house call. Where did you buy the blinds from. Maybe they have an installation service.

  Nevermind. :P We bought them from Spotlight (but they don't have an installation service as far as we know).   

> #8 screw is the gauge of the screw, you would probably need them to be about 1-1/2" long or 40mm.

  These screws look to be about that size. I think they may indeed be #8 gauge. I'll double check this tomorrow actually.    

> As to construction adhesive liquid nails or maxbond will do the job but you really need to drill into the hard brick to get the holes deep enough.  
> Do you have a percussion drill or just a normal drill and you have to use a masonary drill bit.

  The drill I'm using is an Ozito cordless and I'm thinking it may not be powerful enough to get through the hard brick to get deep enough holes for the screws. Its designed for timber, metal, plastic and screw driving (no mention of brick in the manual) so perhaps that is something else I'll need to change. I don't know what a percussion drill is but I'm thinking this one isn't. 
The 6mm drill bit I bought for the job is masonary though.

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## Tommy

As Bazza said you need to use a masonry bit.They have small tungsten teeth on the end of them.Using a hss drill bit can drill a small way in before they loose their edge ,become blue from overheating , then wont drill any further .it will seem like the material you are drilling into has become harder.If you know any carpenters ,that is who you could call to do this for you. :Rolleyes:  
Sometimes using the cheap masonry bits can become useless pretty quickly if you use them at high speed with out a hammer drill. 
Definatly a better tool to use is a rotary hammer drill , if you dont have one you could hire one from bunnings or tool hire shop.There are cheap ones available that come with some bits that would be alright for occasional use.I have seen them for around $70. :Smilie:

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## Barry_White

> Nevermind. :P We bought them from Spotlight (but they don't have an installation service as far as we know).  *Spotlight in Tamworth has a fitting service so I would imagine they would have a fitting service in Sydney.* 
> These screws look to be about that size. I think they may indeed be #8 gauge. I'll double check this tomorrow actually.    
> The drill I'm using is an Ozito cordless and I'm thinking it may not be powerful enough to get through the hard brick to get deep enough holes for the screws. Its designed for timber, metal, plastic and screw driving (no mention of brick in the manual) so perhaps that is something else I'll need to change. I don't know what a percussion drill is but I'm thinking this one isn't.  *A cordless drill wont cut in some of the old bricks in some of the old houses around Sydney. I used to fit the blinds all over Sydney so I know what some of them are like. Especially the old black ones. If they were old sand stocks they wouldn't be a problem so the minimum drill you would need is a percussion drill. You would be able to buy a cheap electric percussion drill from Bunnings that would do the job.* 
> The 6mm drill bit I bought for the job is masonry though.

  *Like Tommy says the cheap masonry bits really aren't up to the job. A masonry bit that is used in a percussion drill has the cutting edges beveled on both edges*

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## Novice_79

Ok cool. 
Guys thanks again for all your advice. 
I'm glad I stumbled upon this site!

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