BauBuche post and beam

Product: BauBuche

All the details on the office building by lattkearchitekten BDA

The light timber surfaces of the post and beam structure with visible columns and beam ceilings shape the overall feel of the room and create a pleasant working environment. The occupier has created room zones of different sizes to suit the workplace requirements. The dividing walls and wall panels in glass and white opaque surfaces follow the structural design and subtly allow visual contact between the adjacent rooms.

The 2 metre wide balcony on the southern side adds extra space and also creates a protected and attractive outdoor area in the close proximity of the park itself. The shade created by the overhang prevents the sun shining directly in, so no technical sun protection is required.

Details

Location

Augsburg, Walchstraße

Constrcution / Planning

2014-2015

Building Class

3

Architects

lattkearchitekten BDA, Augsburg

Engineers
Building services / electrics

JETTER Ingenieur- und Service GmbH & Co. KG, Gersthofen

Timber construction
Building site area

2.783 m²

Ground area

465 m²

Total floor area (TFA)

1.335 m²

Total room volume (TRV)

4.690 m³

Photographer
Flooring contractor

DecoDomus Erhard

Area

310.88 m²

Floor thickness

20×152 mm

Finish

Hardwax oil

BauBuche colour code

No. 100

Substrate

Glued to screed

Construction and material

The main post and beam structure forms a room zone measuring 5.1 m in depth on the north side and another on the south side plus a 2.4 m wide central corridor, where the building’s main supply for ventilation, heating and air-conditioning is located in the suspended ceiling.

A mullion and transom façade with triple glazing, also made of BauBuche, is positioned in front of the column level.

ColumnsGrid: 5, 10 m; BauBuche GL70 (20/20 cm)
Main beamBauBuche GL70 (20/40 cm)
Secondary beamGrid: 85 cm; BauBuche GL70 (12/32 cm)
Ceiling boardBauBuche Q (40 mm)

 

Layout of ground storey

Layout 1st storey

 

Layout of 2nd storey

 

Cross section

 

Isometry

 

Ceiling structure

Floor slab

 

BauBuche flooring20 mm
Cement screed54 mm
Insulating board, soft wood fibre40 mm
Bituminous seal6 mm
Reinforced concrete floor slab180 mm
PE film separating course0,4 mm
Insulation XPS80 mm

Ceiling above ground storey and first storey

 

BauBuche flooring
Cement screed50 mm
Insulating board, e.g., Isover Akustic EP 140 mm
Bound gravel120 mm
Board BauBuche40 mm
Joists120 / 320 mm
The flooring structure with 12 cm deep latex-bound chippings adds weight to the floor to provide positive vibration and noise insulation properties.

 

Roof structure

 

Gravel16 / 32 mm
EPDM seal, single-layer laminated1,55 mm
Tapered insulation EPS (20-240 mm)130 mm
Insulation PUR120 mm
Vapour barrier/emergency seal2 mm
BauBuche Board40 mm
Joists100 / 240 mm

 

Wall structure

Wall structure (timber frame construction for parapet and gable walls)

 

2x Plasterboard2x 12,5 mm
Board OSB-315mm
Cellulose fibre insulation with timber posts 60/240 between240 mm
Paraffin-treated soft wood fibre board35 mm
Battens 30/60/ rear ventilation30/60 mm
Timber formwork vertical, coated21 mm

 

Energy supply

HeatingDistrict heating
CoolingGroundwater wells
Ventilation system:With heat recovery

Envelope:

  • Superinsulated building envelope in a prefabricated timber structure Uw = 0.15 W/m²K
  • U transparent = 0.90 W/m²K

 

Media routing in the central zone

Media is routed in the central zone of the building.

The streamlined BauBuche GL70 joists in the central zone with a cross-sectional height of just 160 mm leave enough space to route all the lines under the joists. Elaborate cutting of the joists is not necessary.

 

Material comparisons, connections and structural details

The great load-bearing capacity of the BauBuche GL70 Beams facilitates a particularly streamline design. This is demonstrated by material comparisons with conventional glued laminated timber GL24h.

BauBuche GL70Glulam GL24h
ColumnsB x H = 200 x 200B x H = 240 x 240
Joist 1st storeyB x H = 200 x 400B x H = 200 x 550
Joist 2nd storeyB x H = 200 x 280B x H = 240 x 450

With the post and beam structure comparatively simple, flexible connections are used.

Connection of the secondary beams to the joists

Right:  Connection of a secondary beam.
Left: Connection of the smaller secondary beam in the central area.

Joist joint with slotted sheet

Storey joint of the main columns

The high column forces are conducted through the joists via 4 dowels D = 20 mm of steel grade S355. The columns are secured in position through structural measures taken by the timber construction company.

 

Processing – An experience report

Working with BauBuche – An experience report by the project manager Jens Moser, Gumpp & Maier GmbH (timber construction company)

How did your first timber construction project involving BauBuche go?

The Eurogen office building was the first project for which we used the new BauBuche material. When I took over management of the project, I was surprised by the small cross sections of the columns and beams. And I am still fascinated by just how streamlined constructions with BauBuche are. This is what makes BauBuche so special in my opinion. Processing and assembly were not without their complications. We had to go through an in-house learning process. Nevertheless, we would certainly use BauBuche again. And I am already looking forward to the next project.

What was your experience of trimming BauBuche?

After we received delivery of the first beams, I was of course struck by the high deadweight. The density of BauBuche is around 800 kg/m3 and the material boasts a corresponding strength. We trimmed the beams on our Hundegger K2. To keep the cutters on course, we had to set the speed of the joinery machine to the lowest track speed. This worked well.

 

Since all the screw holes for BauBuche had to be predrilled, there was a lot of drilling to be done. How was this?

We essentially made the drill holes with a diameter of 6 mm by hand. Spiral drills were great for this. Given the great hardness of BauBuche, the drills became very hot quickly. That’s why the colleagues always worked with numerous drills. After each drilled hole, the machine was changed to allow the drill to cool down. As an alternative, the drills can also be cooled down in an oil bath. I would not, however, recommend this since the oil drops can quickly soil the wood. Compared to softwood, significantly greater drill wear must be anticipated.

Recommendation from Pollmeier: When drilling in BauBuche, fully ground drills ensure the best results; e.g., FAMAG wood drill HSS-G long.

 

Assembly – An experience report

Assembly – An experience report by the project manager Jens Moser, Gumpp & Maier GmbH (timber construction company)

BauBuche is extremely sensitive to moisture. How did you cope with this?

That’s true. Moisture sensitivity is the central issue when assembling BauBuche. We produced the pockets in the main beams with an excess width of 2 mm so that the secondary beams would fit into them easily even if they have swelled slightly. Furthermore, all the columns and beams were given a moisture protection coating (BauBuche varnish from Koch und Schulte GmbH & Co.KG). When applying the BauBuche varnish, particular attention should be paid to the end faces. The beams were carefully stacked with laminated wood and wrapped in foil to ensure moisture protection during transportation and at the building site.

Recommendation from Pollmeier: BauBuche varnish is highly recommended as a protective coating for transportation and assembly. The layer thickness to be applied is 120 ml/m², that is the equivalent of one coat. Particular attention should be paid to the end grain areas – the end faces of the beams: Here we recommend 2 to 3 coats of BauBuche varnish. This is particularly important in the case of columns since the horizontal end faces can be subjected to rough weathering conditions.

How did assembly go?

Despite the many days of rain, assembly of the beams and columns went well. The protective coating more than proved its worth. Despite the varnish we still covered the structure in tarpaulins whenever it rained. The ceiling boards BauBuche Q, on the other hand, were cut to size and delivered untreated directly to the site by the manufacturer Pollmeier. Moisture protection proved more difficult here: We constructed a temporary, rain-proof storage box for the boards on site. The boards were only assembled on rain-free days and, immediately after they were laid, bitumen foil (BauderTEC KSD Duo) was applied to provide protection from the elements.

Were there still water marks on the boards?

Yes, despite our best efforts, there were still a few water marks. These can be removed with oxalic acid, which we did successfully.

 

Update

The BauBuche frame construction of euregon AG won the HolzBauPlus award in the category for new commercial buildings. This prestigious competition takes place every two years under the auspices of the German Federal Ministry of Food and Agriculture and aims at promoting sustainable building methods and materials. Congratulations!

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Advice for architects, engineers, commercial builders and timber construction:

+49 (0)36926 945-560 baubuche@pollmeier.com

Advice on timber, BauBuche and for Pollmeier LVL:

+49 (0)36926 945-163
sales@pollmeier.com

POLLMEIER IS A MEMBER OF GERMANY'S FEDERAL ASSOCIATION OF SAWMILLING AND WOOD INDUSTRIES​

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