To achieve the comfort of a contemporary dwelling in an old dwelling, besides the means, it is best to be advised and prioritize.
Knowing and asking a professional is essential before buying a house to renovate.
Buying an existing property for an average price can quickly require doubling the bet to make it comfortable to live and energy efficient. Poor exposure, dilapidated, difficult access … choice of materials, techniques and finishes can explode the estimated budget in a hurry. VAT at 6% and bonuses in addition, the good companies issue quantified solutions; Do not hesitate to push many doors and work sites in progress to judge on piece.
“There are no miracle recipes for renovation. Some owners will focus on aesthetics and comfort, others on energy consumption. I advise you to surround yourself well before embarking on a construction site, “ explains Gérard Sevrin, manager and technical director at Macors, general contractor of construction and transformation.
For Thibault Frys, in charge of drawing up estimates, the ideal house must be able to evolve: ” Our quotes are hyper detailed, with different variants allowing the client to set his priorities. We can visit the house to be rehabilitated. Without a priori, just to pose a technical look. As a general company, we have a global view. “
Anti-humidity solutions : Formerly, building sealing techniques were not as thorough. Climbing humidity is the enemy of renovation. It must be stopped before undertaking any transformation under penalty of seeing his work reduced to nothing.
The cost per meter is shown here. That is between 80 and 100 € / m current depending on the thickness of the wall to be cleaned. A little humidity in a cellar is not a real problem, but it becomes so when it is transformed into a heated living room (games room, TV room …). Low humidity is important for healthy heating of a room; For the health of the occupants and to avoid degrading the materials.
2. CLOSE THE BUILDING
A) A new roof or not?
If the framework is in good condition, disassembling the old roof and installing new gutters and descents: between 125 and 130 € / m2 excluding VAT using large format artificial slates for a single roof with two slopes.
Natural slate will be almost twice as expensive; The concrete tile is the cheaper solution.
Standing seam zinc coverage (when urban planning permits) still raises the price by 10 to 20%, despite the speed of implementation. Include an extra € 1,000 per roof window. If the roof is in good condition, insulation from the inside with 20 cm of mineral wool is 35 € / m2 excluding VAT to comply with the insulation standard.
B) Walls and floors
The ideal is to pack the building from the outside in a major renovation, but one often wishes to preserve the exterior aspect of a house of character. The fastest and most effective method for the floor is the projection of polyurethane foam (PUR) to create an insulating screed.
Count 15 to 18 € / m2 depending on the thickness; To insulate walls (often irregular) in the same way, it is 20 to 25 € / m2 . Obviously, you will have to add the finishing to the choice: laying tiles (30-80 € / m2) excluding VAT or ceiling – cardboard-plaster or coated – (15-50 € / m2 excluding VAT). Warning that isolating the floor is not always possible, but recommended.
C) Doors and chassis
For 500 € / m2 excluding VAT , delivery and installation included, you will benefit from PVC frames equipped with super-insulated glazing (value U = 1,1).
The more windows you have, the more the note will inflate. If your openings exceed the standard height of 215 cm, you will pay more. Same if you multiply the number of opening frames. Circular and semi-circular windows cost 50% more .
Aluminum is 8 to 16% more expensive than PVC; The steel 15 to 25%. Meranti tropical wood, or other exotic species with the FSC label are 10 to 15% more expensive than the PVC and will require regular maintenance.
For a small house, if all the electricity is to be redone, count 5 000 € for this one position. Not to mention the luminaires obviously, added to this general installation including however a new distribution box (divisional).
As for other renovations, if your house is more than 10 years old, you benefit from a 6% VAT that will have to be added to this amount. In detail, count on average 30 to 50 € per luminous point , 30 € per switch and 50 € per outlet . Beware sometimes of bad surprises when bleeding in the walls.
If you are considering a scalable home automation, multiply at least by two the investment. You will then have dimmer (dimmers), parlophone and videophone.
Allow another 200 to 400 € for the reception of the installation by an officially approved organization.
4. HEATING AND SANITARY
The total floor area is used to calculate the cost of sanitary pipes. The more appliances and water points you have, the more pipes and investments will be made. Average price for placement by appliance (tap, washbasin, toilet, shower, …) from 13 to 16 € / m2 . If your radiators are still performing well, they often do, they are kept.
If your boiler gas or oil is more than 15 years old, you gain to change it to reduce consumption by 20 to 30%. Include an average price of 5 to 6,000 € excluding VAT for the complete installation of your new condensing boiler. For an electric (200 liters) or gas (16 liters) boiler: 750 to 1,200 € excluding VAT . The solar boiler multiplies the setting by four to accumulate hot water. If you place a rainwater tank with pump and filter: 3 000 € excluding VAT .
The kitchen, aesthetic and functional, will evolve. Integrated furniture can be an economical solution. Complex shapes, including angles, weigh on prices. A central island that remains simple is hardly more expensive than one or two angles.
Take a reliable base of solid, durable furniture, supporting the replacement of the laminate worktop with a higher-end material (synthetic stones, real stones or granite, glass …). The same applies to home appliances, sinks, valves … For façade materials, melamine is the most accessible coating with a good level of resistance and aesthetics. At least, 10% to 20% more expensive, the laminate brings a higher level in the same grade of finish. It starts at € 4,000 . For electros and a minimum of furniture.
Here, the budget can explode if you like great luxury. By remaining reasonable, we find “white” sanitary as well as quality fittings at very affordable prices.
That is 400 € for a basin with two basins, the same amount for an acrylic bath, the complete toilet (suspended or not), as well as the thermostatic bath and shower tap. The acrylic shower cabin is an economical solution and a quick placement that goes without long finishes.
For 2 500 € excluding VAT, connecting to arrivals and evacuations, the basic bathroom is already very welcoming. Obviously the spa bath, the multijets which transform it into spa and other options (cabin and diffuser for hammam or sauna) sometimes exceed the price of a beautiful car. Add 500 € for minimalist storage furniture.
Very low energy: investing in technologies
In the case of a complete refurbishment tending towards low energy, if you want to equip yourself with a heat pump (PAC), underfloor heating, you will first go through the complete insulation box of the envelope Building to remove any thermal bridges. Mechanical ventilation will be provided to ensure a healthy air in the house which has become “thermo”.
Ventilation with heat exchanger recovering the calories from the exhaust air discharged will explode your bugdet by dropping it from 5 000 to 7 000 €. The cheapest ventilation systems see this price divided by three. To replace or better, to support the boiler, on the PAC side, different exchange systems exist: count from 6 000 to 20 000 € depending on the type and the power.