Fixing To... Historical Wall Materials
We’ve covered a few tips on fixing to common wall materials such as insulated plasterboard and hollow block, which you’ll find in many modern houses, but what if you happen to live in a period property?
Older construction materials such as stone, cob or wattle & daub may require slightly different methods and extra care when fixing to them, so let’s take a look!
Old Stone Walls
Old cottages can look like they’re straight out of a fairytale, but what if the walls are made from stone, either drylaid or mortared? Drilling into thick old stone walls can really wreck your masonry drill bit, so proceed with caution. If you do need to drill into the stone, it’s a good idea to buy, rent or borrow a hammer drill and use a fresh masonry drill bit.
Depending on what you’re fixing, one option is to attach a sheet of plywood or plasterboard over the stone surface with adhesive (effective turning it into a “Dot and dab” wall) and then fixing into the plasterboard. This can work especially with lighter fixtures, and you can get away with plasterboard fixings like these Rawlplug self-drilling ones or Cobra WallDriller . A handy option for thin materials is Cobra Nylon Toggle.
However, if you end up doing this or are fixing something which covers a large surface area, like a set of kitchen cabinets, be aware that old stone walls need to be able to breathe, ie absorb and release moisture, to prevent problems caused by damp. Over a smaller area this is unlikely to be an issue, but with e.g. kitchen cabinets you need to make sure there’s a gap between them and the wall. For example, you could fix thick timber battens to the stone first using something like Corefix 120 and then attach the cabinets to those with wood screws.
If you can, we’d recommend you put the fixing straight into the stone, using reliable masonry fixings like Cobra TripleGrip, Corefix or Rawlplug frame fixings. If your stone wall is covered in lime plaster, make sure you drill through it and into the actual stone itself, as the lime plaster itself won’t be very reliable for holding fixings. If it crumbles, just go ahead and patch it up after the fixings are in.
If you’re concerned about the fixing staying in the holes, one option is to glue them in with epoxy resin after cleaning the hole of dust. Just be aware that it sets quickly and be ready with a rag or tissue to wipe off any spills! Another trick you can try is to create a wooden “fixing” by drilling larger holes, glueing or epoxying wooden plugs or dowels into them, and screwing your fixture into the plugs with wood screws.
If you’re really struggling to drill into the stone and need to fix a radiator for example, another option is to attach it to an internal wall instead (which is more likely to be a material that’s easier to drill into) or buy a floor standing radiator!
You can find cob walls in period houses particularly in the southwest of England. Cob walls are made of a mixture of clay-based subsoil, straw (or some other fibrous material), water and sometimes lime or sand.
This means thick walls with generally good insulating properties which tend to taper upwards slightly, so you’ll need to be aware of this when fixing anything to them!
Moisture is kryptonite to your cob house. The more moisture that manages to penetrate the cob, the more it dissolves the material which can lead to structural failure (ie your house collapsing, in the worst-case scenario!) External render, which you’ll likely find on cob walls, helps prevent this from happening, but you’ll need to be careful when drilling into it (especially if you’re fixing something to the outside, like an awning or windowbox) and ensure any cracked render is repaired.
Fixing things securely to cob can be a bit of a challenge. With lighter loads, wall plugs like Rawlpug UNO may do the trick, especially if you use the epoxy resin trick mentioned earlier and glue the plugs in. Just be gentle when knocking the plugs in. Longer fixings will give you a better grip, for example the 50mm Fischer DuoPower. The wooden plug or dowel method from earlier may also work as the cob will accommodate it if you hammer it in gently.
For heavy loads such as cabinets, things are a bit trickier. You’ll likely need to resort to building a stud wall in front of the cob to avoid pulling chunks out of the cob wall! You can then fix your cabinets safely using either heavy duty plasterboard fixings like Gripit or wood screws to fix to the studs.
Wattle And Daub
Wattle and daub is a historical building material in which a woven lattice of wooden strips called wattle is daubed with sticky material usually made of a combination of wet soil, clay, animal dung and straw, and covered in plaster. It’s often associated with timber framed houses from the 1500s and 1600s.
As a wall material for wall fixings, it’s unfortunately not very reliable. Simply drilling wall plugs into the plaster and the wattle behind will not give you a very strong grip. However, there are a few fixings you can try for lighter loads.
Geefix is a strong cavity fixing designed mainly for plasterboard, with a large flat piece gripping the wall material from behind. The back plate can also be positioned vertically behind the wooden strips, but as it requires a fairly large hole to install, Geefix recommends using a hole saw instead of the usual flat drill bit to avoid breaking the wattle and daub.
Another option to get a grip behind the wattle is Bladefixer, which is also suitable for lath and plaster walls. For both of these, you’ll want to be very careful when cutting any holes so as not to crumble the plaster – or if the plaster is very fragile, just install all fixings you need to, and then repair the surface all in one go.
For light hooks, you may not need to drill or cut into the wattle & daub at all if you go with light adhesive hooks such as these 3M Command bathroom hooks.
With heavier items, you’ll likely have no choice but to fix them to the wood beams of the frame, as the wattle and daub will simply not support them. The beams are often oak, so be sure to use stainless steel screws as the tannins in the old oak can rot plain steel screws. For heavy picture frames and mirrors, you can also consider picture rails fastened to the beams.