From the construction plan to the finished solid wooden wall
The basic material: side-cuttings from the sawmill MHM® walls are manufactured with a specially
developed plant, the so-called MHM production line in sawmills or carpentry firms. Side-cuttings, which are left over from beam manufacturing form the basic material. The remarkable thing is that what used to be treated as a left-over now has its own value because this side-cutting is the raw material for the MHM® wall. Therefore, this is genuine “upcycling”.
The construction is carried out with the help of 3D CAD software:
Using construction plans drawn up by architects or planers, the MHM manufacturer can produce wall elements CNC controlled from MHM® extremely accurately. There is no more than +/- 1 mm tolerance. Slants, door and window cut-outs, installation ducts etc. are accurately cut out and/or milled.Computer-controlled manufacturing (CAM) results in a high degree of accuracy in accordance with 3D CAD planning and makes subsequent assembly on the building site easier.
The production process is divided into three parts: grooving the individual boards, producing the individual wall plates and the so-called joint, which means the final finishing of the wall plate into a ready-to-install element that is accurate to the millimetre.
In the first stage, the dried boards are grooved which later forms a standing layer of air in the finished wall and consequently results in a better insulation value than with pure solid wood. In addition, a 3 mm lateral rabbet joint is milled which ensures that the side fits accurately and adds extra strength. All the boards are random width and are always 24 mm thick.
In the second stage, the “wallmaster” produces raw wall elements from the profiled boards varying in size from 2 m x 2 m to 3.25 m x 6 m and in thicknesses of 11.5 cm to 34 cm, into which the boards are pressed cross-wise (lengthwise and crosswise) and connected with aluminium groove pins layer by layer. Each board intersection is connected with two nails at the largest distance possible to each other (diagonally). This ensures the highest possible degree of stability.
After the pressing stage, the raw wall element is moved to the CNC panel cutting machine standing in line, where the element is formatted in a third stage and the necessary door and window openings are cut. The drill holes for lifting slings, slots and recesses for heating and sanitary facilities, as well as electrical sockets and other installation preparations are milled into the element by computer-controlled tools.
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Solid, pure wood – that is our secret
Untreated wood without any chemicals
MHM® walls consist of untreated wood. The boards are joined together by aluminium groove pins, the resilience of which ensures extremely stable and strong wall elements. Thus, the MHM® doe not require any glue as an adhesive agent. Due to this permeable construction method and the intrinsic properties of wood, absolutely no vapour
brakes are required for MHM walls.
On the interior, no chemical wood protectors are generally required in timber constructionbecause the drying process makes the wood dimensionally stable and resistant to parasites. On the exterior, constructive wood protective measures reduce the use of wood protection agents to a minimum. Once fitted with insulating elements, the façade of MHM houses can simply be plastered.
High degree of fire retardancy
While construction materials such as brick, steel and concrete are mostly fire retardancy class F30, official measurements confirm that MSM® are actually classed as F90 B. Wood has a further advantage: Due to the material’s low thermal conductivity, heat does not reach neighbouring rooms so quickly. Fires can only spread slowly whilst remaining controllable.
Remarkable heat storage, low thermal conductivity
The solid construction of MHM® walls and the consequent mass forms a much larger heat store than in other construction systems. The thermal conductivity of wood is so low that the surface warms up quickly.
When the indoor temperature drops, e.g. during the night, the high retention capacity means that only the indoor air and not the walls needs to be heated the following day. The so-called “phase shift”, this means the time in which a square metre of wall cools down by 1°K, is up to four times as long as with a brick.
The MHM wall stands out on account of its remarkable insulation value. This is caused by MHM’s unique construction method: The boards are given rabbet joints and are profiled with many small grooves which form an air cushion. These standing layers of air give the MHM wall elements insulation values which are roughly 30% better than with pure solid wood.
Why you should live and work more healthily with the solid timber wall
The MHM® wall consists of untreated wood through and through. Due to the fact that no glue, plastic film or other chemicals are used at all, no foreign matter or solvents which could be hazardous to human health are released.
Glue and plastic film are never really permeable, the natural route of moisture in wood is disturbed which means that the indoor climate is affected in a negative way. This can be avoided by MHM® wall‘s completely open design.
People with allergies will particularly feel the difference and all other residents will also notice the healthy indoor climate of solid wooden walls.
The danger of mould growth and the consequent hazard to the health of inhabitants is avoided as early as in the shell construction stage by the permeable design and by using wood which is a dry building material.
A further plus point is the self-regulating indoor climate of solid wooden houses. The walls and ceilings “breathe” with the MHM® wall because they are constructed in a permeable way and can therefore absorb vaporous humidity, store it and release it again. This characteristic has a positive effect on the inside air humidity and balances out fluctuations, so there is relatively uniform humidity depending on the season.
Wood’s natural inertia and its large mass shield off high-frequency waves effectively. The house therefore constitutes a natural protection zone, for example from mobile phone signals.