On this page, you will find frequently asked questions regarding CLT building and Celt’s services. Hopefully you will find them helpful. You can also submit a question of your own. We will respond to the question and publish new, useful FAQs and answers on this page.
Why is it worth to use Celt Construction Elements instead of just CLT panels?
Celt Construction Elements move the construction process from the construction site to a dry indoor environment and industrial production line.
When only CLT panels are delivered to the site, it leaves lot of laborious work to the construction site e.g. sanding and painting the wooden surfaces, insulation and cladding installation. Basically CLT is then only the load-bearing structure material.
A building’s state of completion can be increased markedly by using Celt Prefab Elements. All visible CLT surfaces are finished, meaning that no trimming, sanding and painting are needed at the construction site. Installation of HVAC can begin immediately, using the milled HVAC apertures of the elements. This reduces the construction site time by weeks. Depending on the desired scope of the delivery, the degree of pre-completion can be increased so that the external surfaces are also ready and doors and windows are installed.
Use of Celt Prefab Elements reduces expensive construction site work and the costs associated with scaffolding, protection, heating and waste. It also markedly reduces the loss of construction material.
The benefits are even greater when Celt Modules are used. Then only module installation, connection to public utilities and the installation of possible structures external to the building, such as terraces, are needed to be done.
If the builder does not use hired workforce and the construction timetable is not critical, savings can be achieved by your own work; just ordering CLT elements you can save on purchasing costs.
Can CLT surface be used for the exteriors of buildings?
Yes. With appropriate treatment, CLT can serve as an exterior surface, as in a log house. In Finnish conditions, some cracking of the surface is inevitable, but this can be handled in a number of ways. Although many CLT manufacturers do not have outdoor use classifications for their products, Celt Construction Elements come with a normal structural warranty for outdoor use.
Will a CLT structure make HVAC or electrical work more difficult?
No. It makes them easier. With Celt Prefab Elements, all HVAC and electrical conduits and apertures are in the right, precise places as planned, which enables very fast plumbing and electrical installation and the use of pre-made HVAC and electrical parts. For example, all ventilation ducts can be pre-assembled and pre-insulated in line. In Celt Modules, HVAC is ready-installed.
Can I have some examples of the surface treatment used in CLT panels?
Yes. Celt will paint the panels in the desired treatment and, upon request, deliver samples of different treatments to help you make the right decision. You can also choose from a range of wooden surfaces and the panel visual direction can be horizontal or vertical.
Can the wall of a CLT house be inclined?
Yes. Thanks to their cross-laminated structures, CLT panels are load-bearing and support the building structure in all directions. This also enables the use of inclined surfaces in structures such as outdoor walls. The panels are cut and worked using a computer-controlled CNC router, enabling a virtually endless range of cutting and shaping techniques.
Can a CLT panel serve as a load-bearing base floor structure?
Yes. CLT technology is compatible with a range of foundation and base floor solutions. Celt Prefab Elements can be used as the load-bearing floor structures. If there is not used underfloor heating system, CLT can be also as the visible floor surface. We use also beam structures as floor structure. Also, the ground-based concrete floor is commonly used floor structure in CLT houses.
Why are there not more CLT apartment buildings?
Many CLT apartment building projects are on the drawing boards, but many times they are delayed by a lack of expertise and vendors of CLT module solutions. In addition, legislation and regulations are not very supportive for wooden apartment buildings, although changes are coming. Modular building method is becoming more commonplace. CLT modules can be the load-bearing structure of apartment buildings. Also LVL (laminated veneer lumber) and MHM (Massiv-Holz-Mauer) are used as structure of apartment building modules.
Can a private builder order CLT panels straight from the CLT manufacturer?
Yes, it is possible. Some CLT panel manufacturers also deliver their products directly to private builders. However, when only CLT panels are delivered to the site, it leaves lot of laborious work to the construction site e.g. sanding and painting the wooden surfaces, insulation and cladding installation. Basically, CLT is then only the load-bearing structure material.
It is important to take account of the overall building project. Millings may be insufficient due to the limitations of CNC machines. For example, the corners of apertures are always rounded, socket drillings are not available on both sides and many manufacturers find drilling into an element challenging. Visible CLT surfaces and milled surfaces always need to be sanded before painting, even if the manufacturer’s delivery includes rough factory sanding. In addition, structural design and fastening supplies need to be planned and calculated. In most cases, a CLT solution should be ordered in the form of ready-made construction elements. Using Celt’s Plug & Live service, you can ensure that the element delivery is comprehensive and the products are adequate for the purpose. We take care of planning, the Celt Construction Elements and warranty-based installation, with fastening supplies, at a fixed price.
- Can I have an implementation based on my own plans?
Will disturbing cracks appear on indoor CLT surfaces?
The right raw material processing, manufacturing conditions and treatment materials ensure that surface cracks on CLT panels are barely noticeable. Anyway, wood is an organic material, so surface cracking can appear in CLT due to humidity and temperature changes. The CLT manufacturer’s surface quality and gluing technology can also affect to the number and type of surface cracks. Various treatment methods (e.g., fluting) and processing tones can also affect the visibility of cracks. Treatment materials can be used to eliminate the living nature of the wooden surface, but this will reduce the benefits of wood with respect to indoor air. The experiences of people living in CLT houses suggest that, rather than being a problem, cracks and organic surface provide the increased level of comfort of an organic material. It is not a problem, it is the feature of wood.
Does Celt deliver houses that are ready to move into?
Celt Modules are ready-to-move apartments. Celt Modules are residences and buildings that are ready to use and move into. In module delivery, the customer is responsible only for the groundwork, foundation and connections to public utilities. We use our network to help our customers find the right partners for carrying out the remaining work.
In case of Celt Prefab Elements, the Celt Plug & Live service concept includes the full design and delivery of the elements, which is always fully installed and at least weather protected. Delivery starts from the ready foundation. For the most extensive delivery, Celt Prefab Elements are installed with exterior finishing and all CLT interior surfaces are finished.
Why is it worth building a house with a CLT structure?
CLT has many advantages in construction. CLT construction means healthier living, more ecological building and a more profitable residential investment. In addition, its unique design options and the longevity of the structure guarantee a higher retail value for your residence. The Celt Plug & Live service makes it easier to begin the project and speeds up its completion as planned. The key benefits of CLT in terms of construction and living can be found here: CLT Technology.
Is CLT construction more expensive than conventional beam or log construction?
Not significantly. The most basic delivery option includes the CLT exterior walls and CLT roof panel of a detached house, which cost a few thousand euros more than a house with a beam-structure. In CLT houses, solid wood tends to be used in other structures because of the speed, architecture, structural simplicity or to ensure a smooth project. In such cases, the base floor, intermediate floor, partitions, stairs, terraces, railings, fences, carport and garden buildings can also be made of CLT, leading to a greater price difference for the materials. Celt Construction Element delivery has a greater degree of pre-completion than a beam-structured prefab element delivery. This often makes direct price comparisons between house deliveries irrelevant. Compared to a log house, the total cost of a solid wood CLT house is highly competitive.