Plastic anchors, fasteners in concrete?

[tinpanalley]

Can I use plastic anchors to fasten a 35lb mirror to a concrete wall? I need two screws.

I go online, I try to research what works best in concrete, I see half the sites saying plastic anchors are fine, the other half saying one must ONLY use metal anchors, wedge anchors, etc.

Let me know if you need further info, photos

 

[Deleted member 174758]

It depends on the concrete. Is this a solid concrete wall or a concrete block wall?

For a light to medium load like yours nylon plugs should be adequate, no need for shield anchors, providing you use big enough plugs, long enough screws and drill the holes accurately enough. In solid concrete I reckon 7mm holes, brown plugs and 5 x 60 or 70mm screws should do it.

 

[Odds]

I'm about to drill holes for a couple of shelves in the bathroom and always use red or brown plugs as the ones they include are always rubbish; skinny yellow things, this time. Meh!

 

[tinpanalley]

It depends on the concrete. Is this a solid concrete wall or a concrete block wall?

For a light to medium load like yours nylon plugs should be adequate, no need for shield anchors, providing you use big enough plugs, long enough screws and drill the holes accurately enough. In solid concrete I reckon 7mm holes, brown plugs and 5 x 60 or 70mm screws should do it.

I can't see whether it's solid or blocks because it's a wall in our apartment. But let's say I don't see any mortar lines at all. I have photos from behind a power outlet. More likely solid wall panels.
These specifically are the ones I have that I'm wanting to use.
I also have these from years ago but their smoothness has always scared me for heavier loads.
I would be using two screws and with a cable as well that I have running in the back through d-hooks. Each screw/anchor of the ones I linked to above is rated at 40lbs. The thing that scares me a bit about metal ones like lead anchors is what you do if they end up just spinning in place in the hole.

 

[Deleted member 174758]

Sorry, but your ur links don't work - they come back with "Access Denied"

In the UK many apartment walls are either MF studwork or cement blocks these days, at least in multi storey blocks, with solid concrete only being used where that section of the wall in structural, e.g. lift/service core walls, etc. More likely that you have blockwork

 

[Odds]

Sorry, but your ur links don't work - they come back with "Access Denied"

In the UK many apartment walls are either MF studwork or cement blocks these days, at least in multi storey blocks, with solid concrete only being used where that section of the wall in structural, e.g. lift/service core walls, etc. More likely that you have blockwork

Me neither, i think it might be Italian(?) 'toggler-alligatora' the link points to, which translates as alligator clips. Doesn't sound right, to me.
Molly Bolts, perhaps, would be the thing if the walls are hollow.

 

[tinpanalley]

Sorry, but your ur links don't work - they come back with "Access Denied"

In the UK many apartment walls are either MF studwork or cement blocks these days, at least in multi storey blocks, with solid concrete only being used where that section of the wall in structural, e.g. lift/service core walls, etc. More likely that you have blockwork

Strange. They're links to Home Depot here in Canada. Should be able to work?
And as far as the walls, this is a 1940s apartment building construction. And I'm in Montreal, Canada.

 

[blup]

Can I use plastic anchors to fasten a 35lb mirror to a concrete wall? I need two screws.

I go online, I try to research what works best in concrete, I see half the sites saying plastic anchors are fine, the other half saying one must ONLY use metal anchors, wedge anchors, etc.

Let me know if you need further info, photos

I would use nylon plugs and 75mm no 10 (5mm) screws.

Blup

 

[Mike13]

Strange. They're links to Home Depot here in Canada. Should be able to work?
And as far as the walls, this is a 1940s apartment building construction. And I'm in Montreal, Canada.

Home Depot are using geolocation to refuse access to people in other countries, helps stop DDOS and reduces load on the server.

 

[Deleted member 174758]

Strange. They're links to Home Depot here in Canada. Should be able to work?

Perhaps HD are blocking us because we are in the UK.

Edit: See comment above

And as far as the walls, this is a 1940s apartment building construction. And I'm in Montreal, Canada.

I have no idea what they were using in Canada 80 years ago. There have been some all concrete buildings erected here, such as those built from pre-cast panels made from the infamous "no fines" concrete - which incidentally are a pain to fix into, but mass concrete isn't that common in domestic work over here. Another problem in that our sizes are all metric, notvall the products are the same, and the terminology is a little different, too.

So the nearest size to 7mm is 9/32in and in the UK nylon (plastic) plugs to fit 7mm holes are generally called "brown plugs" because most manufacturers colour code plugs (red = 5.5mm, brown = 7mm, and so on). The nearest to a 5mm screw is a #10, as stated above, although a 6mm screw (equivalent to a #12) will also fit.

If the plugs you are referring to are Fischer DuoPower plugs:

then they will do the job, even if the wall material is a bit soft or crumbly. I'd still go for the longer screws, 70mm or 2-3/4 to 3in, because they t3nd to wedge themselves in better than shorter screws to resist pull-out

A note about concrete types: if the concrete you are drilling into is heavy structural grade or is of "no fines" type (a lot or large stones in the aggregate with minimal sand or small stone), you will need an SDS drill to make your holes because those types of concrete are so hard

 

[Odds]

then they will do the job, even if the wall material is a bit soft or crumbly. I'd still go for the longer screws, 70mm or 2-3/4 to 3in, because they t3nd to wedge themselves in better than shorter screws to resist pull-out

A note about concrete types: if the concrete you are drilling into is heavy structural grade or is of "no fines" type (a lot or large stones in the aggregate with minimal sand or small stone), you will need an SDS drill to make your holes because those types of concrete are so hard

If the wall's crumbly i tend to fire in a blob of filla to help things set. Our house is pre-war so the walls can be hit n' miss in different rooms.

 

[opps]

Strange. They're links to Home Depot here in Canada. Should be able to work?
And as far as the walls, this is a 1940s apartment building construction. And I'm in Montreal, Canada.

Odd.. none of Home Depots sites seem to be accessible from the UK, neither the USA or Canadian sites.

If I use the opera browser and turn on the "americas" VPN, I can access their site.

I think the DuoPower plugs will be fine.

 

[JohnD]

If the wall's crumbly i tend to fire in a blob of filla to help things set. Our house is pre-war so the walls can be hit n' miss in different rooms.

Builders adhesive is very much better

 

[tinpanalley]

Another problem in that our sizes are all metric, notvall the products are the same, and the terminology is a little different, too.

I think this is one of those things where we unfortunately lean towards ridiculous US measurements. I'm from a part of Canada that is almost entirely metric but some commercial things/products historically tended towards American systems because they were the products being imported before Canada had their own manufacturer. Don't get me started on the history of British North America and how it became Canada, we'll be here all day. Moving on...

The nearest to a 5mm screw is a #10, as stated above

So my set says 8-12 so I guess I'm good with these? I don't get how they can say 8-12, isn't a hole only one size?

If the plugs you are referring to are Fischer DuoPower plugs

It seems Fischer makes them but the ones available here in Canada make no reference to Fischer.

Somebody asked me why not concrete screws..
(I didn't want to get into all this initially because I've found over several years online that today asking anything more than a one sentence question is tantamount to assault to people online who will either ignore you or launch into you for writing "such a long post". Anyway...)

When we hung this mirror a few years ago in a place we were renting, we placed it above a non-functioning fireplace that was brick and then some kind of concrete behind it. I used concrete screws there. Worked great. When I went to do the same here the following happened...
- Screw pilot holes drilled with bit provided in the packaging.
- Concrete screw inserted, but when I started screwing it in, I got about half way and it just wouldn't turn anymore. I even tried gently with the torque of my drill as a driver. So I went back in with the same bit the concrete screws came with and just went in and out gently again thinking I needed to maybe shave one stubborn bump or something. Now the screw slides in and out not gripping anything. It was at this point that I thought maybe it's better to just make this hole a bit bigger and use an anchor. Because I'm clearly not going to be able to use these screws anymore in that hole.

So, that's where I am.

 

[Deleted member 174758]

So my set says 8-12 so I guess I'm good with these? I don't get how they can say 8-12, isn't a hole only one size?

The hole in the masonry is one size - but the nylon plug is compressible to an extent, and wood screws can cut their own thread as they enter. TBH I"d avoid the smaller (#8) screws

Somebody asked me why not concrete screws..

Well, I'm trade, and I neither like nor trust them because if their variable performance...

They are also relatively expensive and they are rarely needed (a bit like resin anchors in that respect)

Maybe your concrete screws are trying to cut into a flat piece if extra hard aggregate in the concrete (e.g. granite or flint)

All I know is that plugs and screws are often good enough for carpentry tasks.