What first plaster or electrical: 3 main installation methods

One of the most important decisions that must be made when beginning any remodeling project is whether to plaster the walls or install electrical wiring first. This choice could have a big effect on the project’s overall timeframe as well as the finish quality.

Plastering and electrical work can be coordinated in three main ways, each with advantages and disadvantages of its own. Comprehending these techniques can facilitate more informed decision-making and guarantee a more seamless renovation process.

These approaches will be dissected in this article so you can select the one that best fits your requirements and the particulars of your project.

Method	Description
1. Electrical First	Install wiring and outlets before plastering. This allows easy access to the walls, but you’ll need to protect the electrical work during plastering.
2. Plaster First	Plaster the walls before installing the electrical work. This keeps the wires and outlets cleaner, but cutting into the finished plaster can be tricky.
3. Combined Method	Do rough electrical installation first, followed by plastering, and finish with installing outlets and switches. This balances protection and accessibility.

It’s important to think about which approach best fits your project when choosing whether to install plaster or electrical work first. Plastering before electrical installation, installing electrical before plastering, or doing both at the same time are the three basic methods. Depending on the particular requirements of your space, the intricacy of the electrical system, and the wall finish you desire, each method has advantages and disadvantages.

Disadvantages of electrical before plastering

Before plastering, what does electrical work entail? Strictly speaking, there are three possible outcomes here: either the wiring is "hidden" in the wall’s body or in the plaster layer, or it is installed in cable channels on top of the finish. The initial two scenarios pique our interest. Because it is more typical, we are thinking about the second option.

Electrical wiring nowadays is more intricate than it was a few decades ago for the following reasons:

• safety standards have become stricter;
• the number and power of electrical appliances used in everyday life have increased;
• new building materials have appeared;
• the requirements for ergonomic conditions, comfort, and aesthetics of housing are becoming more and more important.

Nothing is simpler than to install junction and socket boxes, spread and fasten wires or cables on top of the wall, and then confidently apply plaster! Actually, this leads to multiple issues at once.

Thickness of the plaster layer

Not only are plastering projects time- and labor-intensive, but they are also expensive financially. For a small room, you will need more than one bag of cement, even if you make the solution yourself with cement, water, and sand and minimize the plaster layer. A thin layer won’t work if the walls are made of brick and are uneven. Furthermore, for every centimeter that the plaster coating is thicker, a new building requires an additional cubic meter of mortar; time expenditures rise along with work-related complications like the need for more reinforcement; and plasterers’ pay rises.

You will need to apply a layer of (rough) plaster coating up to 25 mm in order to conceal the wire’s thickness with plaster, particularly if the wire is inside a corrugated pipe. Electrical work prior to plastering is warranted if the leveling layer is 2.5 cm or thicker. It will make sense to plaster first if the plaster layer is less than this amount. Making grooves and installing the wiring after plastering is less expensive than thickening the plaster layer. Furthermore, the final measure "eats up" the room’s available space.

Cable damage

Electrical wiring that is invisible can cause a lot of unfavorable things to happen. Skilled artisans advise doing the following right away, even before plastering, after the wires are laid:

• measure the distances from the corners, floor, ceiling to the edge of the wires;
• draw lines on the wall with chalk indicating the distance;
• write (clearly) the measured values, and also label which room, which wall;
• take a photograph (faster) or sketch it in the form of a diagram on paper.

This schematic will be useful in a number of situations, such as when putting in dowels beneath carpets or pictures.

Wires installed and fastened to walls frequently go undrawn or unphotographed for their subsequent "vision" following plastering. When attaching a frame for hanging furniture or finishing with clapboard or fiberboard, you run the risk of damaging one of the wires with a working tool or dowel.

Forced changes to the project

Changes may be made for a variety of reasons at any point during the construction process. The project does not specify, for instance, whether plastering or electrical work should be done first. In certain cases, the problem is fixed on the spot. The plaster layer may thicken as a result of earlier wiring.

The custom-made furniture will then need to be moved by the home’s occupants. Additionally, that will "drive" into the socket, preventing access. You will have to move the socket because, of course, nobody will remake the furniture. There are other alternatives as well, which could alter not just the sockets’ design positions but also those of other electrical wiring components. It is therefore more advantageous to carry out electrical work while chasing the rough plaster.

Oxidation of joints

Extensions and other connections between them are included in the wiring. Plaster solutions are considered "wet" materials because they contain water, which can seep into even the smallest cracks. However, the solution is actually a solution of salts rather than water, which makes it a dielectric rather than a water-based material. When finished wiring is plastered over, there is a significant increase in the likelihood of wire connections oxidizing. The process of oxidation starts to destroy the contact, and this destruction can lead to burnout in wall boxes, for example.

Therefore, extra precautions must be taken before plastering to shield the installed wall boxes, switches, and distribution boxes from liquid from the solution and the solution itself. The ends of the wires are temporarily insulated and brought out above the level of the wall box top in order to protect them (this presents another issue).

Techniques for preventing solution infiltration into wall boxes:

• sealing the top with masking tape (available to everyone, cheap, simple);
• making "covers" from corrugated cardboard (you can cut as many as you like using a crown with a diameter equal to the diameter of the wall box).

These techniques, though, don’t always keep liquid out of the wall box. Therefore, prior to plastering, all wiring is disconnected.

Installing wall boxes and fittings

Assume for the moment that distinct individuals are working on plastering and electrical projects. The measurements required for plastering (forming an additional vertical plane) are not needed by electricians. Because of this, electricians are unable to pinpoint the precise location of the plaster coating’s surface. It follows that they are limited to estimating the distance at which the top of the wall box "cup" should be placed in relation to the top of the unplastered wall.

Alright, so let’s say that after plastering this top, it turns out to be recessed. In that case, adding more spacer rings and using longer-length self-tapping screws will fix the issue. However, no matter how it is twisted, the socket will appear to have a "bump" if the top "sticks out" above the plaster layer. That is, it might not be possible to achieve the intended outcome, which is for the top of the "cup" to be flush with the finishing surface. After plastering, you will need to "disassemble" the problematic area from the wall using the same techniques used in electrical work.

It is difficult to do markings

The simplicity and ease of marking is a strong argument in favor of plastering’s superiority. Making markings for cable loop tracing on uneven walls and ceilings, as well as taking measurements requiring millimeter accuracy, are more challenging. Laser levels are frequently used by electricians to mark work. A tiny protrusion on the wall surface may obstruct a thin light beam that is installed in close proximity to the wall.

Long ends of wires interfere with plastering

Plasterers apply the rule when leveling walls with mortar. The rule cannot be applied to this portion of the backfill, from the beginning to the end, if the ends of the wires rise above the wall surface. The plasterer needs to use creativity to level the mortar where the wire is sticking out.

The wall boxes, distribution boxes, and other wiring components, in addition to the wire ends, impede plastering.

Only a differential or an RCD will function if the cables unintentionally come into contact with voltage.The plasterer will be spared an electric shock thanks to the circuit breaker, which has tripped.

They won’t, however, spare you from looking for places to break down or from figuring out why you’re tripping.

Pros of wiring before plastering

If there were only drawbacks, electrical wiring would not be installed before plastering, of course. Sometimes, just the benefits mentioned below make this version of the work sequence preferred.

Plastering mesh

Its integrity is required throughout the entire process if, for some reason, a reinforcing mesh is utilized to strengthen the plaster coating or to firmly fix the mortar on the wall surface. The mesh can be cut during chasing, in which case the structure will cease to function as a unit. Therefore, electrical wiring needs to be completed before plastering if reinforcement is required.

SNiP standards

Currently, there are no explicit guidelines in the standards regarding the proper course of action to take, such as whether to lay the wiring first or later.

The new SP 71.13330.2017, clause 7.1.5, which is advisory in nature, states that hidden electrical networks have to be installed and tested before work is completed. In other words, the SP suggests doing electrical wiring before concluding. It is unclear, though, exactly what is meant by "finishing work"—that is, whether rough plastering work falls under this category. It’s likely that the standards will be fulfilled if any of the work sequences achieve the necessary level of finishing.

Absolutely smooth walls

Perfectly smooth walls are the desired outcome for plasterers and finishers. The size of the filler grains and the internal structure of the solution determine the thickness of building mixtures with a given composition (that is, there is a certain gradation of possible layer thicknesses for a particular type of mixture). Moreover, certain solutions shrink—that is, lose volume—when they dry.

Estimating potential shrinkage or precisely measuring a plaster coating sample when chasing is a problem unto itself. The surface of the repaired area is therefore aesthetically distinct from the nearby wall after the groove has been filled with mortar and allowed to dry. "Readability of tracks" has an effect.

Further leveling with priming, puttying, and grinding is needed to eliminate the effect. This comes at an extra expense. And when the electrical wiring is first installed and then plastered, the surface becomes smooth when primer or cover (with grouting) is applied right away. This is also a benefit.

Disadvantages of electrical work after plastering

Let’s now discuss the advantages and disadvantages of a different work order. In this sequence, the walls are plastered first, then the coating is applied, marking, chasing, electrical wiring is installed (into the grooves), "cups" are installed, sockets and switches are mounted, and damaged areas are restored.

Damage to walls during chasing

The consequences of a "shaky hand" are not always avoided, even with expert tool use. Such situations are not unusual when chasing the plaster coating to lay cables, particularly if the plaster coating is thin.

The vertical reinforcement in precast or monolithic concrete houses helps to transmit and absorb loads in the load-bearing walls. On top of it is a 2 cm layer of protection. Thus, in Khrushchev era and panel houses, it is forbidden to chase load-bearing walls for the building’s safety and security. Additionally, chasing floor slabs—or ceilings—is forbidden. You can only chase partitions.

Electricians use a chaser, which has a depth limiter and sets the precise distance between the slots, to maintain the exact chasing depth.

Noisy and dusty work

If running cables and wires directly on the wall is a relatively quiet process, mechanically chasing is a "loud" task that makes noise that reverberates throughout the riser in homes. Its working conditions are determined by this particular situation. For instance, it is legally forbidden to make noise on weekends, and it is only permitted during the day on weekdays.

There are no effective ways to stop the formation of dust clouds when cutting grooves. The wall is sprayed with water to prevent the formation of dust. However, connecting a construction vacuum cleaner to an angle grinder or wall chaser with attachments works better.

Damage to plaster layers

The plaster coating may become compromised when cutting grooves for electrical cable laying (cracks may appear, the layer may come off the base). The finishing layer on the rear of partitions may be damaged. This is particularly common when utilizing impact tools, like hammer drills. Frequently, the plaster’s reinforcing mesh is damaged during cutting with an angle grinder. It takes time, effort, and money to restore what has been destroyed.

Avoid chasing the plaster coating applied to concrete, metal, and other low-adhesion materials to prevent damage.

Cost

To properly seal the grooves after the electrical wiring is installed, you will need to hire plasterers. Removing the debris, dusting the walls, priming, setting up the mortar, and plastering will all be necessary. This is all labor and time. Additionally, paying plasterers with mortar is a waste of money.

In order to compare the expenses of the two approaches, let’s figure out how much it will cost to chase and thicken the plaster layer by half a centimeter.

If the cable must be laid in a groove that is at least one centimeter deep, the cable can rise up to 0.5 cm above the base if the plaster layer is designed to be one centimeter thick and placed on the wall. To make the cable invisible as a scar, you will need to increase the coating’s thickness throughout the wall by this amount.

We will compute the additional plaster consumption for a room with a perimeter of (5 + 4) x 2 = 18 m and a ceiling height of 2.7 m as an example.

Wall and ceiling area, F, is equal to 18 x 2.7 + 5 x 4 = 68.6 m^2.

With a layer of 0.5 cm, the widely used Volma-layer mixture has a consumption per 1 m2 of 4.5 or 5 kg.

11 packages, or 4.5 x 68.6 = 308.7 kg, are required.

30 kg (packages) are priced at 450 rubles. It will require 450 x 11 = 4950 rubles for the plaster mixture.

One point five minutes of groove costs 100 rubles. That means we can create a groove that is roughly 49 linear meters for the same amount. On the other hand, 10 two-meter grooves, or just 20 m grooves, will be needed for a 45 m2 room of the same height that has 25 points installed (partially double, triple sockets, and a double switch). – 2000 rubles. Our example indicates that a room requires fewer grooves, resulting in lower chasing costs.

If plastering is done first, not electrical work – advantages

Among them is the capacity to install all devices (switches, sockets) according to the project the first time around. Plastering tools do not harm the cable, nor do they cause the wire connections to oxidize. Additionally, wiring maintenance and repair are made simpler. Thus, you only need to open one groove to replace a wire.

Compliance with planning solutions

One benefit is that the first approach implements design solutions for the placement of outlets and other electrical network components. The amount of unoccupied space in the room doesn’t get smaller. When installing the frame, electricians can avoid damaging the cables if the walls are lined with plasterboard, also known as dry plaster. This method allows them to read the route accurately.

Convenient installation of fittings

The electricians themselves gouge out recesses for socket boxes and electrical boxes during the installation process. This makes it possible to install them the first time with the edges flush with the finishing coating at the appropriate depth. It is not necessary to leave the wire ends longer than is required.

Combined method

You can gain some benefit by doing some electrical work prior to plastering and the second part afterwards. Thus, when using the combined method, rough plastering comes after the lines are laid. The switches with sockets themselves, wall boxes, and distribution boxes are installed last.

Coordination of teams of electricians and plasterers

It is preferable if the home’s owner does all repairs, including the plastering and electrical. Nonetheless, these tasks are typically carried out by groups of experts or invited artisans. As a result, their consent is needed.

The order of work varies depending on whether electrical or plastering work is to be done first.

The following is the order to follow if installing electrical wiring is a top priority:

1. Electricians are invited who run the cable along the ceiling (or subfloor), then install distribution boxes, install flush-mounted boxes on the walls for (sockets and switches), and connect wires to them.
2. The plasters that carry out wall plaster are called.
3. Electricians are aligned by the sockets in terms of plaster level, install the shield.
4. The finishes perform the finish (glued wallpaper, paint, etc. D.).
5. An electrician is invited to install switches, sockets and wiring wiring.

If plastering comes first and not electrical work, the sequence is altered:

1. The plane of the plasters is invited, prepares the walls. They are done with a black leveling with a solution.
2. Electricians come in, perform design markings, stroke the walls, cut out the recesses for the sockets. Install the sockets, lay the wires, mount sockets, switches, connect the network to the shield, test and de -energize the stroke for sealing. Here it is possible that electricians do not install the "filling" in the socket boxes, but perform this work, as well as testing and commissioning at the final stage (after the delivery of the object by finishers).
3. Finishers complete the finishing.

When using a combined approach, electricians are invited first and finishers follow.

The sequence in which you plan to complete the electrical and plastering is a crucial decision in any building or renovation project. There are advantages and disadvantages to each method, whether you decide to plaster first, install the electrical system first, or take a combined approach.

Although it provides a clean finish, plastering before the electrical system is installed may make wiring more difficult to add later. Conversely, installing the electrical system first makes adjustments easier, but it might necessitate touching up the walls afterwards. In order to balance both, the combined approach necessitates meticulous preparation and coordination.

When determining the sequence, take into account your unique requirements, the intricacy of the project, and the team’s expertise. Whichever approach you decide on, preparing ahead of time and collaborating with knowledgeable experts will help guarantee a seamless workflow and a superior outcome.

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