Which screws for 2 jobs

[Lijong]

Hi all

Firstly what screws do I need to screw into your normal type of worktop underneath? Not solid wood but the chipboard type of looking one. I am making a bedroom desk with some grey worktop for my son. He has some heavy-duty legs for them ( https://www.amazon.co.uk/dp/B075NT3...olid=1I8OUO46RAEKK&psc=1&ref_=lv_ov_lig_dp_it ) so either which screws or which fittings/bolts etc. The legs are heavy as the desk is 8 foot long

Secondly, I need to screw some wood onto a wall internally. The wall is just plasterboard (dot and dab) and behind it is some type of breeze block/grey block. The wooden baton is quite heavy so will screw in concrete screws do it, or hammerfix screws or ? The wood is perhaps 6 inches by 2 inches and 5 foot long so a fair weight.

Many thanks as always

 

[FrodoOne]

1. Chipboard screws.

2. a. You will need to screw into the "Breeze-block", if it is backing the plasterboard.
2. b. Screw into any studs (if they exist,) if it is not immediately backing the plasterboard.

For 2. a. Depending where you "strike" the breeze-block", it could be only 20 mm to 30 mm thick or it could be much deeper.
Particularly if the point of penetration is deeper than 30 mm, masonry/concrete screws should work.

However, if you have any doubt concerning the solidness/reliability of the material in the penetration concerned, insert a (larger) suitable wall plug but ensure that the hole is first also filled with a fast setting epoxy-resin compound - to soak into the block material and also coat the wall plug.
When the epoxy resin has set, an ordinary wood screw should be used into the wall-plug.

For 2. b. Wood screws.

 

[foxhole]

You need to determine the block type , thermalite blocks require quite different treatment as they are soft and ordinary plugs won’t hold .Most other types of block are fine with standard plugs.

 

[Lijong]

Super, thanks so much for the info. Much appreciated

 

[Lijong]

1. Chipboard screws.

2. a. You will need to screw into the "Breeze-block", if it is backing the plasterboard.
2. b. Screw into any studs (if they exist,) if it is not immediately backing the plasterboard.

For 2. a. Depending where you "strike" the breeze-block", it could be only 20 mm to 30 mm thick or it could be much deeper.
Particularly if the point of penetration is deeper than 30 mm, masonry/concrete screws should work.

However, if you have any doubt concerning the solidness/reliability of the material in the penetration concerned, insert a (larger) suitable wall plug but ensure that the hole is first also filled with a - to soak into the block material and also coat the wall plug.
When the epoxy resin has set, an ordinary wood screw should be used into the wall-plug.

For 2. b. Wood screws.

Can you give me a link to the fast setting epoxy-resin compound? There's so many epoxies out there I don't want to get the wrong one. Would sincerely appreciate it. Thanks

 

[FrodoOne]

Can you give me a link to the fast setting epoxy-resin compound? There's so many epoxies out there I don't want to get the wrong one. Would sincerely appreciate it. Thanks

Since I am in Australia, I cannot give you advice as to the brands available in your country.

However, you will need only a small quantity of a two part epoxy resin adhesive.
I suggest that you look under the words in "bold" and select a reputable brand name - which should be available at a local hard-ware store.

 

[johnny2007]

https://www.screwfix.com/p/fischer-...VV-DtCh19qAruEAQYAyABEgL-t_D_BwE&gclsrc=aw.ds

 

[foxhole]

Since I am in Australia, I cannot give you advice as to the brands available in your country.

However, you will need only a small quantity of a two part epoxy resin adhesive.
I suggest that you look under the words in "bold" and select a reputable brand name - which should be available at a local hard-ware store.

Have never found the need for resin when fixing in over 40years of diy .

 

[JohnD]

some type of breeze block/grey block

if the house is 50 years old or less, I expect they are foamed/lightweight/insulating concrete blocks, which are rather weak and crumbly.

In a poor surface, I have never needed epoxy (it is widely used for reinforced concrete repairs and fixings outdoors with stainless screws) but I have had good results with ordinary builders adhesive. This also works with soft bricks and mortar joints.

Drill your hole so it is deep enough and wide enough for your plasplug
Remember that your screw and plug must penetrate well into the block. Ignore any length in the plaster because it has no strength.
Clean out all dust and loose material with a vac or waterjet
Inject the glue, starting with the nozzle deep in the hole so there is no air bubble at the back, and withdraw it as you inject

press the plasplug into the hole so that it is surrounded by glue and any excess squeezes out at the front. You can use a screw, a couple of turns into the plug only, as a handle

wipe or knife away the excess

leave to set overnight

the next day you can wind out your handle, and screw into the plug which will be held firmly and will not rotate or come loose

the adhesive transmits the expansion forces into the wall. As there is no air bubble it is prevented from expanding too far or splitting. The glue fills any minor cracks in the brick. As you have allowed the glue to set it does not squirt out of the hole.

In damp conditions or outdoors, use a weatherproof adhesive and give it extra time to set.

If you have a number of holes to do, drill them all first, then clean them all, then fill and so on. Doing each individually takes a long time.

 

[FrodoOne]

Have never found the need for resin when fixing in over 40years of diy .

You might not have found a need for such a product BUT, if the substrate is crumbly, an epoxy resin infusion will improve the situation.

It is all a matter of "degree" and can be judged only by an individual in a particular situation.

Of course, if the screw/plug pulls out after the fixing has been "secured", the individual has judged things wrongly.

The term "belt and braces" does come to mind.

 

[Deleted member 174758]

Have never found the need for resin when fixing in over 40years of diy .

Me neither. Even in trade I've only used resin anchors to support steels which will be carrying large weights (typically 10 tonnes and upwards)

There are a large number of relatively low cost anchors out there specifically designed for use in lightweight building blocks such as Thermslite and Poroton, etc. Take a look at the Fisher or Rawl catalogues to see what I mean. To my mind resin/epoxy is just expensive and completely OTT

BTW did you know that you can first fix timber pattresses onto Thermalite so long as you skew the nails?