Dot and dab walls are hated by many and loved by few BUT in this article I’m going to be chatting about how to attach anything to one of these walls with zero hassle. When you know what fixings to use dot & dab can actually be a pleasure to work with. Hopefully you’ll learn to love it as much as I do after reading this.
You can watch the full video here:
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Quick summary of products used
If you can’t be bothered reading all the stuff below I’ll cut to the chase -- here’s a list of everything discussed in the above video:
- Fischer red wall plugs
- Fischer LDF / GP Plasterboard Wall Plugs
- Fischer DuoPower 6mm fixings
- Corefix Heavy Duty Dot & Dab Fixings (24 x)
- Fischer wall bolts / shield anchors (M8 x 60mm)
- Expanding Metal Anchors for Hollow Walls (M5 x 43mm & 52mm)
- Fischer Expanding Metal Anchors for Hollow Walls (various sizes)
- Fischer Drywall Anchor HM Pro Setting Tool
- Forgefix Cavity Anchor Setting Tool (cheaper alternative)
- Nylon Spacers (various sizes)
- For a bigger list of other fixings and tools I use visit this page
A brief history of dot & dab walls
Dot & dab has been pretty common in the UK since the 1970’s. It basically involves ‘gluing’ plasterboard (drywall) to the bare blockwork wall using blobs of an adhesive similar to plaster. It’s a special drywall adhesive designed for the purpose and is much denser than traditional plaster. Dot & dab has many advantages over traditional wet plastering finishes:
- You have an additional cavity behind the drywall
- Better sound and heat insulation (no more cold walls!)
- Much faster to apply (vid of whole room drylined in 16 mins!)
- A flatter generally more even & predictable wall surface
- Can be painted much sooner
- Gives a service void for cables, pipes etc.
- Makes it easy to add new services
- Useful void for running speaker cables, network cables etc.
- You still have the benefits of a solid wall
The ‘solid wall’ bit is probably the bit where most people fall down. You tap the wall, think it’s hollow, use a hollow wall fixing and wonder why it doesn’t work. So here’s my number one tip with dot & dab:
Dot and dab: In some situations you need to treat dot and dab like a hollow wall and in some situations you need to treat it like a solid wall.
Dot & dab often also gets called drylining, even if a full wet coat of plaster is applied to the boards. Some builders / plasterers prefer to just tape and fill the joints between boards using a plasterboard joint compound. Some prefer a full, final skim coat of wet plaster. Obviously the latter means you need to wait a lot longer before painting.
How to tell if you have dot & dab?
If your house was built in the UK from the 1970’s onwards, all solid walls are likely to be dot & dab drylined. You can tell by knocking on the wall -- some areas will sound hollow and some will sound completely solid. The dabs of adhesive are normally around 150-200mm in size and around 300mm between each dab. There’s no hard and fast rules for where the dabs are located and this will be down to the individual technique of the dryliner. Sometimes they follow quite a predictable pattern, sometimes the dabs are seemingly random.
How know if it’s dot & dab or a stud wall?
Sometimes it can be easy to confuse a dot & dab solid wall with a stud hollow wall. Generally speaking on the stud wall even when you knock where a stud is located the wall still won’t sound totally solid. Whereas if you tap the wall where there’s a ‘dab’ the wall should sound totally solid. Also the hollow sections of a stud wall will sound a lot more hollow than the hollow sections of a dot & dab wall. Sorry for all the hollows. If in doubt, drill a small test hole in to a hollow section. If you feel the drill bit hitting blockwork within about 20-30mm of the wall surface, then it’s probably dot & dab. If the drill bit doesn’t hit anything, other than possibly insulation, then it’s probably a stud wall.
How to attach ANYTHING to a dot & dab wall
Before I start, please don’t drill through any pipes or cables -- watch this vid. I’m going to cover a number of different scenarios here, from really light stuff like pictures and mirrors through to really heavy stuff like giant fancy radiators. Here’s a quick summary of the fixings I’m using:
Light weight items
For lightweight stuff such as mirrors and pictures I like to use a single 6mm Fischer DuoPower plug and a 10ga x 1¾” or 5mm x 40mm screw. Obviously use a screw length suitable for the item you’re attaching to the wall. I also sometimes use Fischer GP fixings in hollow sections and normal Fischer red plugs on the dabs. You could also use plugs such as the Rawlplug Uno. The DuoPower plugs have the advantage that they can be used in both the hollow sections and the solid sections.
Medium weight items
For slightly heavier stuff such as really big pictures, mirrors, floating shelves and the like, I prefer to run two plugs back-to-back. The deeper plug will be in the blockwork and the outer plug will either be in a dab or a hollow void. The inner plug can be any standard wall plug designed for solid walls -- such as the Fischer DuoPower or a bog standard red wall plug. Same applies for the outer plug IF you hit a dab. BUT if you’re in a hollow section then the outer plug needs to be suitable for hollow walls. A bog standard red plug won’t work. So for the outer plug in a hollow section I like to use the Fischer DuoPower. You could also use something such as the Fischer GP fixing. The DuoPower has the advantage that you can use it for ANY of the scenarios mentioned, so you don’t need to be messing on with different plugs depending on whether or not you’ve hit a dab.
Heavy items on dot & dab
For heavy stuff on dot & dab I like to use either the Corefix fitting or for complete peace of mind a wall bolt (shield anchor). The Corefix fixings are great for things like kitchen cupboards, bookcases and other items of furniture. Wall bolts give you a fixing so strong that the wall is likely to come down before the fixing -- great for giant heavy radiators, really heavy wall units and the like. In my example I’m using an M8 x 60mm wall bolt using a 14mm diameter drill bit. These are my ‘go to’ wall bolts. They’re strong enough to support just about anything and not so long that you run the risk of blowing out the other side of the blockwork with your SDS drill. Obviously us the size appropriate to what you’re hanging on the wall.
Curve ball -- expanding metal anchors?
A lot of folk think you can’t use expanding metal anchors on a dot & dab wall but you absolutely can. You just need to make your initial hole deep enough that the anchor can be fully inserted prior to opening it up using a setting tool. I ALWAYS use a proper setting tool with expanding metal anchors. Providing you’ve got a wide enough cavity between the drywall and the blockwork then these fittings will work just fine. The cavity size can be a bit random with dot & dab so there are situations where there’s just not enough space for the legs to expand properly behind the plasterboard. This is pretty rare though.
A quick note about aircrete blocks
Older UK houses (1960’s to 2010’s) commonly use concrete blocks of varying density for the inner leaf of a solid wall -- often called breeze blocks. In newer houses these are rapidly being replaced by lightweight blocks known as aerated concrete blocks or ‘aircrete’. Common brand names include Thermalite and Durox. These are much easier to work with and have better insulating properties BUT they’re a nightmare to attach things on to.
The Corefix fittings mentioned above do work in aircrete as do wall bolts in some situations. You can try using other fixings designed for solid walls but you might struggle depending on the density of the blockwork. There are products such as the Fischer Aircrete Anchor and I’ll be covering those in more detail in a later article -- so watch this space!
Last updated: 6 Jun 2019
Originally published: 6 Jun 2019