Installation of Alveus granite sink – step-by-step guide including trap and faucet

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Installation of the Alveus granite sink – complete installation procedure including trap and faucet

A granite sink is one of the products where quality installation is just as important as choosing the right model. Even the best composite granite sink can become a source of problems if it is installed hastily, without proper sealing or with an undersized trap. In this guide, I will go through the entire installation process of the Alveus granite sink step by step – from the first unpacking to the test filling. I will also consider the specifics that differ from the installation of a standard stainless steel sink and point out the errors I repeatedly see during service visits.

If you are still choosing the sink itself, I recommend reading our articles How to choose an Alveus granite sink – hardness, color and material resistance and What size sink do you need – how to measure the cabinet and choose the right dimensions, which will help you get oriented before you start the installation.

What you need before starting the installation – tools and materials

A granite sink is significantly heavier than a stainless steel equivalent of the same size. Composite consists of 70–80% natural granite stone and an acrylic-based synthetic binder. The weight of a standard single-basin model with an overhang ranges from 12 to 22 kilograms – depending on the dimensions and wall thickness. Double-basin models can reach up to 30 kilograms. Therefore, for the installation, it is advisable to have a second person, at least during the phase of inserting the sink into the cutout in the countertop.

Before the actual installation, prepare the following tools and consumables:

Adjustable wrench or combination wrench (size 32, or adjustable)
Neutral silicone sealant (not acetic/acidic!) in white or transparent color
Sealant gun
Mounting pliers or a monkey wrench
Screwdriver – flat and crosshead
De-greaser (technical isopropyl alcohol or acetone)
Cloth and paper towels
Extended screwdriver rod or special wrench for installing the faucet under the countertop
PTFE sealing tape (Teflon)
Water level (at least 60 cm long)
Pencil, measuring tape

If you are buying a sink as part of a set – for example, SET ALVEUS INTERMEZZO 130/81 + TONIA Chrome Faucet – you have the advantage that the faucet is selected directly for the given sink model and the openings are dimensioned so that they fit well together. With such sets, the question of the compatibility of the mounting hole diameter is eliminated, which must always be verified when choosing a faucet separately.

Preparation of the cutout in the kitchen countertop

The Alveus granite sink is installed using a method of cutout with upper or lower edging – so-called undermount (bottom mount) or topmount (top mount with rim). The vast majority of models from the Intermezzo, Cadit or Atrox series are designed for top mount, where the rim of the sink lies on the surface of the worktop and is sealed with silicone.

The cutout in the countertop must have precise dimensions. Alveus provides for each model the so-called "cutout size" – this is always a few centimeters smaller than the total external size of the sink, because the rim must have enough space for support. Typical values are:

Width of cutout = width of sink minus 2× width of rim (usually 20–40 mm)
Depth of cutout = depth of sink minus 2× width of rim

Always cut the cutout before installing the sink, not after. With laminated wood countertops (MDF with a laminated surface), protect the edges of the cutout with transparent varnish or special sealing agent for panel furniture – the moisture that inevitably occurs during sink operation would otherwise cause the edges to swell and the laminated surface to peel. This is one of the most common problems I encounter during service visits after 2–3 years from installation.

After cutting the cutout, check whether the edges of the countertop are perpendicular and straight – any irregularities should be sanded down with sandpaper. Then vacuum the sawdust, degrease the area around the cutout with isopropyl alcohol and let it dry thoroughly. Silicone will not adhere sufficiently to a wet surface.

Pre-assembly – what to assemble before inserting the sink into the cutout

This is a step that many amateur installers skip and later regret. Before inserting the sink into the cutout, it is much more convenient to assemble all components on the sink that would be very difficult to access later – especially the drain valve (waste outlet) and the trap, possibly also the supply faucet.

Installation of the drain valve

The drain valve (outlet) is inserted into the drain hole of the sink from the bottom or top depending on the design. In most Alveus models, it is mounted from the top – rubber sealing rings are placed under the outlet, the outlet is inserted into the hole and from the bottom it is tightened with a nut, or with a hook wrench. Important: the rubber sealing ring must sit evenly along the entire edge of the hole. If the ring is deformed or misaligned, a leak will occur.

Neutral silicone under the rubber seal of the outlet is not necessary if the rubber is new and in good condition. However, for models with an overflow (spillover) it is recommended to apply a thin layer of silicone in addition, as the overflow is structurally more prone to minor leaks when a large amount of water is present.

Installation of the faucet

The faucet is mounted into a pre-prepared hole in the sink (or in the countertop next to the sink – depending on the model). The holes in Alveus granite sinks are mostly 35 mm in diameter, which corresponds to the standard mounting diameter of most kitchen faucets.

Procedure:

Remove the lower sealing washer from the faucet (usually plastic or rubber).
Push the faucet through the hole from the top.
From the bottom of the sink, slide on the sealing washer and the securing nut.
Tighten the nut by hand, then tighten it with a wrench – not too much, so that the rubber seal is not deformed and the granite material around the hole does not crack.
Connect the flexible supply hoses to the body of the faucet (usually G 3/8", but always check the thread).

Sets such as SET ALVEUS INTERMEZZO 30/91 + BATERIE DELOS 91 or SET ALVEUS CADIT 40/55 + BATERIE RUTA CHROM are designed so that the basin fits precisely into the sink cutout without the need to enlarge the hole. With these sets, you usually also receive the necessary supply hoses.

Application of silicone and installation of the sink into the cutout

This is a critical phase that must be done correctly the first time – once the silicone has hardened, it is difficult to remove the sink without damaging the countertop. Apply the silicone to the underside of the sink rim, not on the countertop. Apply an even bead of silicone along the entire edge of the rim – no breaks are allowed, otherwise water can seep under the rim and eventually damage the countertop.

The recommended thickness of the silicone bead is 5–7 mm. When placing the sink on the countertop, the silicone will compress to a layer of 1–2 mm, which is optimal for sealing and aesthetics.

Gently lower the sink with pre-installed components into the cutout – ideally with the help of another person. The first contact of the silicone with the countertop is crucial – gently press the sink along the entire edge, or tap the rim with your palm to evenly distribute the silicone. Do not rock the sink from side to side, as this can cause deformation of the bead and the formation of air pockets.

Securing with brackets

After the sink is in the correct position, proceed to secure it using mounting brackets (clamps). These brackets are included in the sink package – the number depends on the model size. Typically 4–8 pieces. The brackets hook onto the lower edge of the sink and are tightened to the underside of the countertop.

Fastening procedure: always proceed in a crisscross pattern – first the front left and back right brackets, then the front right and back left. This ensures even pressure on the rim along the entire edge. After tightening all brackets, manually check for any gaps between the rim and the countertop – if any exist, tighten the bracket in that area.

Excess silicone that has oozed out from under the rim should be wiped away immediately with a damp cloth or a special silicone scraper. Cured silicone is much harder to remove and can leave marks on the laminated countertop.

Installation of the trap – types and procedure

The trap (P-trap) is a mandatory part of the drain system for a kitchen sink. Its purpose is to maintain a water seal that prevents odors from the sewer from entering the kitchen. For Alveus granite sinks, several types of traps are available:

Classic bottle trap – simple, easy to clean, minimum height of 180–200 mm below the sink drain hole
Flat trap (low profile) – suitable for low cabinets (height from 80 to 130 mm), less bulky
Pop-up trap – drain valve with a lifting plug controlled by a lever or cable directly from the sink
Trap with automatic drain valve (waste kit) – combines the drain valve and trap in one, simplifies installation

If you have chosen the model ATROX 50 černý 91 + pop-up trap, the trap is part of the package and is specifically designed for this sink. The pop-up valve is operated by gently pressing on the drain stopper – it will lift or lower, and no external lever or cable is required. The installation of this system is also described in more detail in our article How to correctly install a pop-up trap and drain for a kitchen sink.

Installation procedure for a bottle trap

Connecting to the drain outlet: The trap is connected to the bottom of the drain valve with a threaded connection. Wrap 2–3 turns of PTFE tape around the thread, then install the trap and tighten by hand + half a turn with a wrench.
Adjusting the position: Rotate the trap so that the outlet points toward the waste pipe in the wall. A bottle trap is usually rotatable 360 degrees.
Connecting to the waste pipe: A plastic corrugated hose (flexible hose) or rigid plastic waste pipe is inserted into the wall waste coupling and the other end is attached to the trap outlet. Check the sealing – the rubber gaskets must be evenly seated in the groove.
Sealing the connections: It is not necessary to seal plastic threaded connections of the trap with neutral silicone if original rubber gaskets are used. Apply silicone only to the connection with the waste pipe in the wall if there is a risk that the sealing may be insufficient.

Double sink models – trap for two basins

With a double sink (for example, the Intermezzo model range with two basins), there are two options:

Two separate traps – each basin has its own trap, both draining into a common waste; simple installation, but they take up more space in the cabinet
Combined trap with a connecting hose – one trap body serves both basins; more space-saving, but in case of a blockage, the entire system must be disassembled

The topic of choosing between single and double sink basins is also covered in the article Single or double sink – which is suitable for your kitchen.

Connecting the water supply hoses

After successfully securing the sink and assembling the trap, it is time to connect the faucet to the water distribution. Kitchen faucets from Alveus and other brands are usually supplied with supply hoses with a G 3/8" thread on both ends. The plumbing outlets in the wall or cabinet (angle valves, so-called "angle stops") must have the same thread – this is the standard situation in modern kitchens.

Procedure:

Shut off the water supply – ideally the angle valve directly under the sink. If there is none, shut off the main water shutoff valve for the apartment or house.
Secure the supply hoses to the faucet body (blue = cold water, red or no color = hot water). Use PTFE tape on the thread – three turns are sufficient.
Secure the other end of the hoses to the angle valves. Again, use PTFE tape on the thread.
Tighten all threads firmly, but without excessive force – brass threads can be stripped.
Open the angle valves and immediately check all connections for leaks. Wipe the connections with a cloth and let them remain under pressure for 2–3 minutes – if they remain dry, the connection is watertight.

For models with a longer reach of the faucet spout – for example, the sink ZOOM 10 NAT – check that the water stream is directed into the center of the basin and not onto the sink walls. The granite material is resistant, but long-term inaccurate aiming of the stream to one spot can lead to the formation of slight surface erosion in older models with a lower granite content.

Test filling and leak check

After completing all connections, the test operation follows. Procedure:

Plug the sink drain with a stopper or pop-up valve.
Slowly fill the sink with water – monitor the connections of the drain valve from below. If it drips, immediately shut off the water supply and tighten the nut, or replace the rubber gasket.
Let the filled sink stand for 5 minutes – check whether the water level drops (which would indicate a leaky seal).
Open the drain valve and monitor the flow through the trap. Any dripping at the trap connection should be resolved by tightening the thread or replacing the gasket.
Check the connection of the trap to the waste pipe in the wall – this location is the most common source of leaks in flexible hose connections.

After a successful test operation, let the silicone under the sink rim cure – at least 24 hours, ideally 48 hours. During this time, you can use the sink normally, but avoid mechanical loading (e.g., sitting on the sink edge or placing heavy objects on the rim).

Common installation errors with granite sinks – what to avoid

Over the years of working with custom installations, I repeatedly encounter several errors that can complicate sink operation for years to come:

1. Acetic (acidic) silicone on a granite sink

Acetic (acidic) silicone reacts with the mineral matrix of the granite composite and can cause surface erosion at the contact point. Always use neutral silicone – either sanitary neutral or construction neutral. Look for the label "neutral" or "neutral cure" on the silicone packaging. Acetic silicone is easily recognized by its characteristic vinegar smell during application.

2. Over-tightening the clamps

The granite composite is very hard, but not infinitely resistant to point pressure. Over-tightening the clamps can lead to the formation of micro-cracks in the sink rim, which are initially invisible but may spread over time. Tighten the clamps firmly, but "feel" the material – once you start to feel resistance, make at most half a turn.

3. Installing the sink without protecting the edges of the cutout in the countertop

Laminate worktops are very sensitive to moisture at the edges of the cutout. Without protective coating or sealing, the edges will start to swell within a few months and after 2–3 years, the countertop around the sink may be irreparably damaged. This is one of those errors that appears late, but is very costly to repair.

4. Incorrect orientation of the trap

The trap must have its drain neck directed toward the waste outlet in the wall or floor. If the waste hose is too long and forms a loop, a secondary siphonic effect may occur, which will "suck" the water seal from the trap. The waste hose should have a straight, smooth slope of 3–5% downward toward the waste – without horizontal loops.

5. Not sealing the sides of the faucet with silicone

If the faucet does not have a pre-installed gasket or the gasket is not sufficiently rigid, water may leak into the faucet hole during manipulation of the faucet (e.g., turning the spout). Seal the base of the faucet with neutral silicone – a thin 3 mm bead is sufficient and will not be visible after curing.

Maintenance and care after installation

A granite sink requires minimal but regular maintenance after installation to retain its original appearance. Our article Cleaning and maintenance of a granite sink – what to use and what to avoid covers this in detail, but I summarize the basic rules here:

Rinse the sink with clean water and dry it with a microfiber cloth after each use – this prevents the buildup of limescale
Do not use abrasive cleaning agents (powders, wire brushes) – they will scratch the surface
For strong stains (coffee, red wine, oil), use a mild sanitary cleaner or a baking soda solution
Once every six months, treat the sink with a thin film of mineral oil – this enhances the matte surface and intensifies the color
Check the silicone seal around the rim once a year – if it starts to crack or peel, cut away the old silicone, clean the area, and apply new silicone

The topic of choosing the color of a sink and its long-term durability is discussed in detail in the article Which granite shade to choose – comparison of colors (black, white, gray, bronze).

Most frequently asked questions (FAQ)

Do I need to call a professional plumber to install a granite sink, or can I do it myself?

Installing a granite sink is manageable on your own with sufficient skill, although you will need a second person to handle the heavy sink. Critical steps – correct application of silicone, even tightening of clamps and tight connection of the drainage system – require patience and precision. If you are unsure about working with the plumbing system, it is better to entrust the water connection to a plumber – it is a short task, usually taking about one hour.

What thickness of worktop is supported by the Alveus sink brackets?

The brackets included with Alveus sinks are mostly adjustable and can accommodate a worktop thickness from 22 to 55 mm, covering standard laminate worktops (38 mm), thinner IKEA worktops (28 mm), and thicker stone or ceramic worktops. For thicknesses above 50 mm, it is advisable to use extended brackets, which can be purchased separately.

Why does a new trap smell after installation, even though it is new?

A new trap often smells because the water seal is not yet sufficiently filled, or because the waste pipe in the wall is loose around the trap inlet and odorous air is entering around the seal. Check whether the water seal in the trap is actually filled (pour a glass of water into the sink). Seal the area around the trap inlet with a gasket or silicone. The issue of odors from drains is also covered in our article Common problems and issues with granite sinks – cracks, drain, sealing.

Can I install a sink into a ceramic (stone) worktop?

Yes, Alveus granite sinks can also be installed into stone, ceramic, or Dekton worktops. In this case, it is recommended to use an epoxy adhesive instead of silicone (stone adhesive for natural stone), or a combination – epoxy for strength and silicone for surface sealing. The cutout in the ceramic or stone must be made with a professional diamond-coated cutting disc – a standard wood router is not suitable. It is not necessary to apply a protective varnish on the edge of the cutout in the stone (stone does not swell from moisture).

Which trap should I choose if I have very little space under the sink (e.g., only 100 mm)?

For low spaces under the sink, there are special flat traps with a body height of 60 to 100 mm. An alternative is a horizontal bottle trap, which lies on its side and takes up a height of only 70–80 mm. With models that have a pop-up drain valve, the drain body is compact and flat traps fit directly on them. Important: check that the flat trap has a water seal of at least 50 mm – otherwise it is not effective against odors from the sewer.

What to do if the sink wobbles after installation and is not stable in the worktop?

Instability of the sink after installation indicates that either the silicone is not yet cured (wait 48 hours), or the clamps are not tightened enough. In the worst case, the cutout in the worktop is slightly larger than the sink rim and the rim has no support along the entire edge. In this case, shims (e.g., from EPDM rubber of 3–5 mm thickness) inserted between the sink rim and the edge of the cutout will help – they will fill the gap and prevent movement. In any case, silicone should be applied sufficiently to fill any possible gap.

Conclusion – what not to forget when installing a granite sink

Installing an Alveus granite sink is a project that a skilled DIY enthusiast can handle even without deep plumbing experience – provided they proceed systematically, do not neglect the preparation of the cutout, use the correct silicone, and allow enough time for the silicone to cure. The key to long-term satisfaction is thoroughness at each step: from preparing the surface through pre-assembly of components, proper application of silicone, even tightening of clamps, to test operation.

Alveus granite sinks are designed to last for decades of intensive use – but only if they are installed correctly. A good installation is an investment that pays off in the form of trouble-free operation and the preserved aesthetic appearance of the sink for many years.

If you are considering a specific model, take a look at our sets such as SET ALVEUS INTERMEZZO 130/81 + BATERIE TONIA Chrome, where the sink, faucet and trap system are designed as a whole – which greatly simplifies not only the selection, but also the installation itself. Alternatively, take a look at the full range in the category Alveus, where you will find models in various sizes, colors and configurations.

Do you have a question about this topic?

Having trouble deciding or dealing with a specific situation in your home? Write to us – we are happy to help.