Available via license: CC BY 4.0
Content may be subject to copyright.
* Corresponding author: lars.olsson@ri.se
Moisture safety in CLT construction without weather protection –
Case studies, literature review and interviews
Lars Olsson1
1RISE Research Institutes of Sweden, Division Build Environment, Building Technology, Sweden
Abstract. This project aims to expand understanding of how cross-laminated timber (CLT) constructions,
including joints, connections and attachment points, are impacted by precipitation during construction. The
project’s case studies have been based on
measurements of moisture contents and
material sampling as well
as microbiological analysis during the construction stage of the structure. The study does not include control
of remediation. A literature review and interviews with seven individuals also were conducted. The results
are based on two case studies with a total of four buildings. The field measurements show microbiological
growth in all buildings and essentially on all investigated floor
structures
. Of a total of 200 analysed
measuring points, half had some growth and about a third had moderate or extensive growth. Based on the
outcome, it seems difficult or impossible to avoid the appearance of microbial growth during construction
with CLT without weather protection. The literature review shows that microbiological analysis of CLT is
extremely rare in both laboratory and field studies, which indicates that there are obvious shortcomings in
the scientific work in practical studies. However, there seems to be good awareness in the literature that
theoretical studies often conduct mould growth risk evaluations. In the survey, half of those interviewed
believed that remediation was needed only in the case of growth visible to the naked eye. There appear to be
no moisture safety assembly methods or solutions for CLT construction without weather protection or
declaration of the critical moisture conditions for CLT products. As a result, it is recommended that weather
protection is used, preferably complete weather protection.
1 Introduction
1.1 Background
There are many advantages of wood as a building
material. High bearing capacity with low dead weight,
flexible solutions with high prefabrication levels and fast
building processes, relatively good insulating properties
in relation to many other framing materials, financial
advantages and en
vironmental advantages are some of
the explanations for the increased use of wood in larger
buildings. The building industry’s major focus on
resource efficiency means an increase in timber
construction, particularly the large increase of building
in modules of cross-laminated timber. Many modules are
purchased from other countries in Europe where the use
of weather protection is non-existent. A new
phenomenon for Sweden in large-scale timber
construction is timber building suppliers that have
partially adopted European building methods and
building without weather protection, see Figure 1, in the
form of tents and instead attempting to minimise weather
impacts and aiming to manage to dry up before
moisture-related problems occur. There is a belief in the
industry today, even internationally, that CLT’s dense
wood constitution allows moisture safety construction
even when exposed to precipitation. There is, however, a
lack of verified documentation for this belief.
Fig. 1. Ongoing assembly of CLT frame without weather
protection in central Sweden.
1.2 Purpose
The project aims to expand understanding of how cross-
laminated timber (CLT) constructions, including joints,
connections and attachment points, are impacted by
precipitation during construction and how to manage
moisture safety. This will enable the industry to
determine weather-protection needs.
E3S Web of Conferences 1
72, 10001 (2020)
NSB 2020
http://doi.org/10.1051/e3sconf/2020172 010 01
© The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative
Commons Attribution License 4.0
(http://creativecommons.org/licenses/by/4.0/).
1.3 Scope and focus
The project involves following the construction of the
structure of four seven-floor buildings located in two
different areas of the country. Each building is followed
up with instantaneous electric-resistance moisture
measurements and sampling for microbiological analysis
of solid wood structure during construction as far as
practically possible within the fra
mewo
rk of the project.
The surrounding climate conditions both indoor and
outdoor are followed up and the climate is assessed with
mould risk simulations. The project also includes an
interview study of seven individuals (site managers,
project engineers and consultants) with experience of
CLT constructing without weather protection. A
literature review looking at moisture and mould is also
conducted.
The moisture safety plans for the construction
projects are documented before the start of construction
and construction is then followed up with random
sampling to evaluate how the plan is actually followed
by moisture experts on the construction project.
The project focuses on moisture and microbial
growth in CLT construction. It is aimed at solid wood
building systems with assembled CLT panels assembled
using mechanical attachments on site. The study does
not cover completion of the building envelope, insulation
and interior and exterior surfaces nor highly
prefabricated construction systems where CLT panels
are assembled using insulation, installations, carpentry or
any complete surface layers straight in the factory. This
research project has not included follow-up of
remediation efforts
2 Literature review
2.1. Regulations and specifications
The Swedish Building Code makes clear demands on
moisture safety [1]
. The general advice is that buildings,
building products and building materials should be
protected from moisture and dirt during the construction
period. Control that material is not damaged by moisture
during the construction period should take place through
documented inspections, measurements or analyses. The
general material and work specifications for construction
[2] require “Wood materials and wood products to be
protected from moisture during and after assembly to
avoid microbial growth and other problems”.
2.2. Literature review
Moisture effects on timber have been studied previously
[3, 4] and appropriate weather protection has been
developed and studied over many years [5-7]. CLT
handbooks and published national and international
recommendations recommend that CLT be protected
from moisture [8-10].
Mould growth on wood can begin immediately at
high humidity and exposure to water at favourable
temperatures [11, 12]. “Wood is a material that easily
grows mouldy and the mould can grow quickly if the
conditions are favourable” [13]. A critical requirement
for microbial growth is moisture, and a relative humidity
over 75% or a moisture content of over 15% have been
shown to be sufficient moisture levels to allow mould to
grow at favourable temperatures and duration. Since
wood can have different moisture contents at 75%
relative humidity depending on whether the material is
absorbing moisture or drying out, known as hysteresis,
the critical moisture content can vary. During drying out,
the critical limit is over 18% moisture content [14].
Wood sill plates and floor studs exposed to 24-hours of
water and then more or less prevented from drying out
immediately have a great risk of mould growth [15].
Mould growth is of
ten invisible to the naked eye, so
detection requires magnification using a microscope [4,
16].
A general literature review of over 30 publications on
CLT has been done, [3, 8, 10, 17-47]. It indicates that
microbiological analysis of CLT exposed to critical
moisture levels or standing water is unusual, only one
practical study did microbiological analysis [30]. It
seems that there is often a
lack of scientific knowledge in
field and laboratory studies since the consequences of
critical moisture content are not examined using
microbiological analysis. The result is that in those cases
it is not possible to say whether mould has developed or
not, except when it is visibly obvious. Several theoretical
studies, however, do note the risk of mould growth based
on mould risk simulations. These theoretical studies,
however, rarely include the critical components that take
the longest to dry. Many studies note that more research
is needed on moisture in CLT
.
3 Interviews
Interviews have been conducted with seven individuals
with experience of CLT construction without weather
protection. These individuals come from different
companies and from different areas in southern and
central Sweden. All the individuals have experience of at
least one building project without weather protection and
several have experience from multiple projects. Most
have extensive experience from the bui
lding industry.
The interviews covered such as questions as: Why is
construction done without weather protection? What
methods are used to reduce water exposure? What is
critical moisture content? Is mould growth a problem?
How is this checked? Is mould visible for the naked eye?
Is unseen mould a problem? How is mould growth
remediated?
A summary of the responses indicates that most feel
that there is a large difference in project costs between
having and
not having weather protection. Although
moisture safety was planned for, the construction
projects these individuals were involved in took place
without weather proofing, which is contradictory since
this type of planning is to lead to moisture safety
construction. Remediation was probably included in the
planning since all those surveyed, used remediation to
address moisture. About half of the individuals felt that
E3S Web of Conferences 1
72, 10001 (2020)
NSB 2020
http://doi.org/10.1051/e3sconf/2020172 010 01
2
only remediation is needed when there is visible growth
even though all of the individuals know that mould
growth can be invisible. Few knew that the National
Building Regulations specify a limit [1] for critical
moisture content at 75% relative humidity for materials
and products that lack documentation. Everyone,
however, responded that the critical moisture content
was landed at 15–18% and several noted that these
values may not be exceeded when the material is
incorporated into the building. A common method of
removing growth seems to be sanding.
4 Case studies
4.1. Four buildings
The construction of the structure for a seven-floor office
building in western Sweden, Figure 2, was monitored
using measurements. The building frame con
si
sts of
seven floors of laminated columns and CLT floor
structures. The floor structures consist of seven layers
with planed timber with a total CLT thickness of 230
mm and the upper layer with a thickness of 40 mm. The
frame has also been braced with steel columns and steel
floor beams. The CLT moisture content at delivery was
12%. The frame began to be built in January 2018 and
was divided into three stages where half of the building’s
frame, stage A, was built to
floor structure five. Then the
second half of the building was built, stage B, to the fifth
floor. Each floor required approximately up to three
weeks for assembly. Stage C began from the fifth floor
and the roof was made watertight at the end of July
2018.
Three seven-floor buildings in central Sweden were
studied as their frames were built, see Figure 1 and 3.
The building frames consist of CLT w
alls and CLT floor
structures. The floor structures consist of 5 layers with
planed timber with a total CLT thickness of 200 mm and
the upper layer with a thickness of 40 mm. The exterior
walls had a thickness of 200 mm and the interior walls
were between 140 and 200 mm thick CLT. The CLT
moisture content at delivery was also 12%. The wood
frame of the first building was assembled in December
2018 and the roof was watertight in the beginning of
March 2019. The second building began to be assembled
in January 2019 and the roof was watertight in mid-
March 2019. The third building began to be assembled in
March 2019 and the roof was watertight in mid-May
2019.
Fig. 2. Frame construction at the case study in west Sweden
and snow on the floor structures. Assembly of CLT frame
without weather protection.
Fig. 3.
Ongoing assembly with water standing on the floor
structure after precipitation in central Sweden.
4.2. Moisture safety efforts during construction
The reason for building without weather protection is
primarily financial. The projects included planning for
moisture safety and a moisture specification document
was produced. This work has been followed and
monitored regularly by the contractor’s moisture safety
manager and the developer’s moisture expert. Methods
for attempting to limit water expos
ure were planned, and
in cases where the consequences of moisture build up
and microbial growth cannot be avoided, then these are
to be remediated. Several different methods were tested,
such as taping, see Figures 3 and 4, covering joints or
holes with plywood boards, covering the edges of floor
structures with felt paper, and separating wood columns
or CLT walls from the floor structures by placing them
on steel stands, plastic blocks or sound and vibration
pads. Water was removed with a wet vacuum cleaner.
The plan was for each floor structure to be exposed to
the weather for at most 1–2 weeks and that they could be
exposed to water from precipitation.
E3S Web of Conferences 1
72, 10001 (2020)
NSB 2020
http://doi.org/10.1051/e3sconf/2020172 010 01
3
4.3. Could the moisture safety plan be followed?
The CLT provider had no problem meeting the specified
12% moisture content at delivery of these projects.
Moisture measurements were conducted about every
other or every third week and were documented by the
contractor’s moisture safety manager and/or the
developer’s moisture expert. It proved difficult to keep
the tape attached during precipitation while assembly
took place and some
times the
tape fell off. It was also
difficult to seal uneven surfaces and connected openings
in the floor structure. The conclusion was that it was not
possible to completely seal using tape. It was also
difficult to ensure that the seals created with boards and
plywood remained sealed. Since the leaky parts of the
floor structure were located in about the same spots
vertically, water was able to continue to several lower
floor structures since these were also leaky at the same
points
, s
ee Figures 5 and 6.
Fig. 4. Taped floor structure joints.
It proved difficult to remove water quickly and with
larger leaks it was difficult to vacuum away all of the
water in a timely fashion. Since most of the floor
structures were exposed to water, they had a high
moisture content on these surfaced until they were dried.
Remediation of surface
s consisted of sanding, sawing
with a circular saw in openings, and other measures, and
there was more remediation work than planned. This
information was provided by the moisture safety
manager or the developer’s moisture expert.
Fig. 5. On several occasions, water pooled on the floor
structure. Precipitation ran down primarily from the above
floor structures.
Fig. 6. Pooled water on floor structure in central Sweden.
Prec
ipitation ran down from the
above floor structures.
4.4. Ambient climate
Data on the immediate surrounding outdoor weather
conditions for the case studies in west Sweden and
central Sweden were taken from nearby weather stations
[48]. The weather stations were located about 10
kilometres from the buildings. Measurement data for
outdoor conditions, such as relative humidity,
temperature and precipitation, see for example Figure 7,
were taken from
the S
wedish weather services’ database
[48].
Fig. 7. Precipitation in mm rain per day and cumulative in mm
rain during construction stage in central Sweden.
The indoor conditions have been followed up
regularly with continual measurements
of air relative
humidity in the rooms and the air temperature on some
of the floors where the buildings have been covered or
sealed.
Measurement uncertainty for the continual
measurements (Protimeter Hygrotrac) at the central
Sweden site for relative humidity is estimated at ±4%
and ±0.5 ⁰C for the temperature. The west Sweden site
used the logging system Celsicom and the sensors
TH501A. The sensors were new and were calibrated at
delivery. They were not calibrated at the end of the
measurement period.
Evaluation of air (relative humidity and temperature)
were done using mould risk simulations based on the
E3S Web of Conferences 1
72, 10001 (2020)
NSB 2020
http://doi.org/10.1051/e3sconf/2020172 010 01
4
mould resistance design (MRD) model [49] with a
critical dose on 17 days for planed spruce in accordance
with the model.
The analyses showed no risk of mould growth at all
related to either the outdoor air or indoor air. On the
other hand, precipitation data [48] has been analysed, see
for example Figure 7, and compared with the assembly
periods, see for example Table 1, and this has shown that
most floor structures were exposed to precipitation
during construction before floor structure above or
protective roofing was installed.
Table 1. Approximate times when respective floor was
installed, roofs became dense and the temporary heat supply
started, at several floors in the buildings in central Sweden.
Phases
Building 2
Bu
ilding 3
Building 1
Floor 2
2018-12-
03
2019-01-
14
2019
-03
-04
Floor 3
2018-12-10
2019-01-
21
2019
-03
-11
Floor 4
2018-12-
17
2019-02-
04
2019
-03
-18
Floor 5
2019-01-07
2019-02-
11
2019
-04
-01
Floor 6
2019-01-
14
2019-02-
18
2019
-04
-08
Floor 7
2019-01-28
2019-02-
25
2019
-04
-15
Roof
2019-03-
04
2019-03-
18
2019
-05
-21
The heat
on
2019-02-18
2019-03-
25
2019
-05
-13
4.5. Field measurements during frame
construction
4.5.1 Measurement procedure
Instantaneous moisture content measurements have been
conducted and have occurred with intervals usually from
three weeks to a month during construction of CLT
structures. Measurement points were placed on
horizontal surfaces, next to horizontal surfaces or on
vertical surfaces (both interior walls and externally on
external walls) also exposed to splashing water from
horizontal surfaces, primarily on surfaces where water
can pool or where drying opportunities are limited.
These measuremen
t points were selected to be well
spread out on each floor, see Figure 9, to represent large
parts of the buildings, based on indications or
assumptions that they have also been exposed to
precipitation or simply as random samples. Reference
points for measurements have also been select at points
not exposed to precipitation or having possible exposure
to insignificant moisture amounts.
Moisture measurements were conducted using
resistance measurements, Protimeter Timbermaster,
t
ogether with hammer electrodes with insulated
electrodes/steel pins at depths of 0, 10, 20, 30, 40, 60
mm from the top of the floor structure, in timber, in
between timber in connections gap and in CLT panel
joints, and near edges and end grains. This project has
shown that measurements in connection gaps are
equivalent to something between measuring surface
moisture content [3] and moisture content in timber [50],
depending on the width of the connection gap between
timber. These measurements have used the indicated
methods with certain deviations. In part, reported
measurement values are based on single measurements
instead of the average value of three measurements.
The instrument was adjusted appropriately for spruce
wood. Temperature compensation did occur.
Measureme
nt uncertainty is estimated at ±1.5% within
the range 8–25% moisture content. Values below 8%
moisture content were reported as 8% and values above
25% were reported as 25% moisture content.
Material was sampled using either hammer and
chisel, see Figure 8, or a core drill to reach deeper into
connection gaps, see Figure 9, or panel joints.
Measurements of the top sides of floor structures under
the sound and vibration pads were done diagonally
downward with long insulated steel pins. Since the
outer-most layer of the walls had a thickness of 20 mm,
both layers were often measured. The samples were
taken in the field and were examined in the laboratory
under stereo-microscope at 10 to 40 times magnification.
To quantify growth, a preparation from the material
surface is made, which is studied at magnification of up
to 400 times. The
preparation is made by scraping part of
the surface with a sharp preparation nail or by taking a
tape impression of the surface. These are then placed in a
drop of lactic acid with cotton blue or alternatively a
drop of potassium hydroxide solution on a microscope
slide and then covered with a cover glass. The
microbiological analyses are based on a defined method
[51] and the analysis results are provided in a four-point
scale: no growth, limited growth, moderate growth or
extensive growth.
Fig. 8. Sample taken from the top side of the floor structure
(CLT) under the sound and vibration pads and inner walls
(CLT). The surfaces have been stained primarily by
discoloured water.
E3S Web of Conferences 1
72, 10001 (2020)
NSB 2020
http://doi.org/10.1051/e3sconf/2020172 010 01
5
Fig. 9. Sample taken with a core drill in the connection gap
between two timbers from the top of the floor structure (CLT).
4.5.2 Results
The moisture content measurements for all case studies
showed that of 300 surface measurement points at 0 mm
measurement depth, about one quarter ha
d a moisture
content of 19% or more. One of the locations with the
largest percentage of elevated or high moisture content
was in the bottom of the connection gap between timber
in the top layer where about half of the measurement
points had a 19% moisture content or higher.
The case study in west Sweden had 51 of 66 samples
with microbial growth, the equivalent of 77 percent of
measurement points. There was moderate to extensive
growth at 58 percent of measurement points. At the case
study in central Sweden, a third of 135 sample points
had microbial growth. A fifth had moderate to extensive
growth. The highest percentage with growth came from
the top of the floor structure under the sound and
vibration pads with 63 percent and hal
f had moderate to
extensive growth. In the connection gaps between timber
in the floor structure in the upper most CLT layer, about
half of the samples showed growth with 16 percent
having moderate to extensive growth. At moisture
content measurements in the middle of timber or in the
second layer, relatively few had elevated moisture
content. It seems that water does not easily absorb into
the perpendicu
lar fibres or through glued layers. Growth
was found at several locations, see for example Figure
10, on most of the floor structures, which indicates that it
is significant.
In locations with mould growth, the moisture content
varied from low to high moisture content depending on
whether there was ongoing wetting, if it was still moist
or if the moisture had dried, at the time of sampling.
There were also measurement points with ongoing
wetting which had not yet received mould growth. No
growth was detected at locations not exposed to water.
Fig. 10. Measurement point number and locations for one of
the floor structures and building in central Sweden and the
results. Green indicates had no growth, orange had limited
growth and red had moderate or extensive growth.
5 Conclusions
Of a total of 200 analysed measurement points, half had
some growth and about a third had moderate or
extensive growth. Based on this study’s results, it seems
difficult or impossible to avoid t
he emergence of
microbial growth during construction with CLT without
weather protection. As such, the building regulations [1]
and [2], could not be met. Thereafter, significant
remediation work was to have been performed at all four
case studies, but the results of this remediation do fall
with this study’s focus.
The mould growth is caused by exposure of the CLT
to precipitation in the form of free water. No growth was
detected at locations not exposed to water. This is as was
expected since the mould risk simulations did not show
any risk for growth when no water exposure occurred.
Mould growth is often invisible and cannot be
detected with the naked eye. Detection requires
microbiological analysis. There seems to be a general
ignorance both nationally and internationally of how to
detect microbial growth on CLT since it is rarely
included in practical studies.
There appear to be no moisture safety assembly
methods or solutions for CLT construction without
weather protection or declaration of the critical moisture
conditions for CLT products. As a result, it is
recommended that weather protection, preferably
complete weather protection, be used.
E3S Web of Conferences 1
72, 10001 (2020)
NSB 2020
http://doi.org/10.1051/e3sconf/2020172 010 01
6
6 Future research needs
More knowledge is needed about critical moisture
conditions for mould growth on CLT and possibilities of
remediation of CLT due to mould infestation.
The support from SBUF (the Swedish construction industry’s
organization for research and development) is gratefully
acknowledged.
References
1. Boverket, Building Regulations, BFS 2011:6. 2017,
The Swedish National Board of Housing, Building
and Planning: Karlskrona, Sweden.
2. Svensk-Byggtjänst, AMA Hus 18, in HSD
Konstruktioner av längdformvaror av trä i hus. 2018,
Svensk Byggtjänst:
Stockholm.
3. Esping, B., J.-G. Salin, and P. Brander, Fukt i trä för
byggindustrin. 2005, Stockholm: SP Sveriges
Provnings- och Forskningsinstitut.
4. Olsson, L., Moisture Conditions in Exterior Wooden
Walls and Timber During Production and Use, in
Chalmers, Civil and Environmental Engineering,
Gothenburg, Sweden. 2014, Chalmers University of
Technology: Gothenburg, Sweden. p. 101.
5. Axelsson, K., et al., Väderskyddad produktion -
Möjligheter och erfarenheter, 11259. 2004, FoU-
Väst: Göteborg.
6. Larsson, B. and L. Söderlind, Väderskyddad
produktionsmiljö- Framtidens byggande. 2006, FoU-
Väst: Göteborg.
7. Brycke, E. and B. Martinsson, Väderskydd - En
lathund för entreprenören, ID:13499
. 2018, SBUF
Svenska Byggbranschens utvecklingsfond: Göteborg.
8. Gustafsson, A., KL-trähandbok, Fakta och
projektering av KL-träkonstruktioner. 2017,
Stockholm: Svenskt trä. 186.
9. Olsson, L. and K. Mjörnell, Väderskyddat byggande
eller omfattande fukt- och mögelkontroll av
fuktexponerat virke, konstruktioner och KL-trä?
Byg
g & Teknik, 2017
.Nr 5.
10. Finch, G., High-Rise Wood Building Enclosures.
ASHRAE, 2016.
11. Sedlbauer, K., Prediction of Mould Growth by
Hygrothermal Calculation. 2001, Fraunhofer-
Institute for Building Physics: Holzkirchen.
12. Viitanen, H., Critical condtions for the mould growth
in concrete and in other materials contacted with
concrete -
durability of concr
ete against mould
growth (VTT W6). 2004, VTT Technical Research
Centre of Finland: Espoo, Finland. p. 25.
13. Johansson, P., et al., Kritiskt fukttillstånd för
mikrobiell tillväxt på byggmaterial -
Kunskapssammanfattning (SP Rapport 2005:11).
2005, SP Sveriges Provnings- och Forskningsinstitut:
Borås.
14. Nevander, L.-E. and B. Elmarsson, eds.
Fukthandboken -
Praktik och teori "Moisture design
manual" 2nd ed. 1994, Svensk Byggtjänst:
Stockholm. 538.
15. Olsson, L. and K. Mjörnell. Laboratory investigation
of sills and studs exposed to rain. in International
Building Physics Conference (IBPC). 2012. Kyoto,
Japan.
16. Johansson, P., A. Ekstrand-Tobin, and G. Bok, An
innovative method for evaluating the critical
moisture level for mould growth on building
materials. Building & Environment 65, 2014. 81(2
July 2014): p. 6.
17. Schmidt, E., L., et al., HOW MONITORING CLT
BUILDINGS CAN REMOVE MARKET BARRIERS
AND SUPPORT DESIGNERS IN NORTH
AMERICA: AN INTRODUCTION TO
PRELIMINARY ENVIRONMENTAL STUDIES, in
CLEM+CIMAD 2017, II Ibero-American Congress
on Construction Timber. 2017, National University
of Northwestern Buenos Aires: Buenos Aires,
Argentina.
18.
Singh,
T., D. Page, and I. Simpson, Manufactured
structural timber building materials and their
durability. Construction structural timber building
materials and their durability, 2019. 217: p. p.84-92.
19. Glass, S., et al., CLT hanbook, Cross- Laminated
Timber (Chapter 10), U.S. Edition, ed. E.
Karacabeyli and B. Douglas. 2013, Pointe-Claire,
Canada: FPInnovations.
20. McClung, R., et al., Hygrothermal performance of
cross-laminated timber wall assemblies with built-in
moisture: field measurements and simulations.
Building and Environment, 2014. 71: p. p.95-110.
21. Wang, L. and H. Ge, Hygrothermal performance of
cross-laminated timber wall assemblies: A stochastic
approach. Building and Environment, 2016. 97: p.
14.
22. Kukk, V., et al., Impact of cracks to the hygrothermal
properties of CLT water vapour resistance and air
permeability, in 11th Nordic Symposium on Building
Physics, NSB2017, 11-14 June 2017, , S. Geving and
B. Time, Editors. 2017, Energy Procedia:
Trondheim, Norway. p. 5.
23. Dietsch, P., et al., Monitoring building climate and
timber moisture gradient in large-
span timber
structures. Journal of Civil Structural Health
Monitoring, 2014. 5: p. 12.
24. Espinoza, O., et al., Cross-Laminated Timber: Status
and Research Needs in Europe. BioResources, 2016.
25. Lepage, R., Moisture Response of Wall Assemblies of
Cross-Laminated Timber Construction in Cold
Canadian Climates. 2012, University of Waterloo:
Waterloo, Ontario, Canada.
26. Liisma, E., et al., A case study on construction of
CLT building without preliminary roof, in Forum
Wood Building Baltic. 2019: Tallinn, Estonia.
27. Mjörnell, K., Olsson, L., Moisture Safety of Wooden
Buildings- Design, Construction and Operation.
Journal of sustainable architecture and civil
engineering, 2019. 24, nr 1(1).
28. Nairn, J., Cr
oss laminated timber pr
operties
including effects of non-glued edges and additional
cracks. European Journal of Wood and Wood
Products, 2017. 75: p. 10.
29. Scotta, R., et al., On the anchoring of timber walls to
foundations: available strategies to prevent wood
deterioration and on-site installation problems, in
XIV International Conference on Building Pathology
and Construction Repair-CINPAR 2018.
2018,
Procedia Structural Integrity.
30. Nore, K., J. Mattsson, and M. Austigard, Cross
Laminated Timber vs. timber frame walls in water
damage – comparing drying and mould growth, in
10th Nordic Symposium on Building Physics, 15-19
June. 2014: Lund.
31. Srisgantharajah, J. and S. Ullah, En studie av
fuktinnhold i massivtre - Oppfuktings- og
uttø
rkingsprosessen, A study of water content in
E3S Web of Conferences 1
72, 10001 (2020)
NSB 2020
http://doi.org/10.1051/e3sconf/2020172 010 01
7
cross- laminated timber - The wetting- and drying
process., in Fakultet for miljøvitenskap og teknologi
Institutt for matematiske realfag og teknologi. 2015,
Norges miljø- og biovitenskapelige universitet.: Ås,
Norway.
32. Kordziel, S., et al., MOISTURE MONITORING AND
MODELING OF MASS TIMBER BUILDING
SYSTEMS, in Wolrd Conference on Timber
Engineering, August 20-23. 2018: Seoul, Republic
Korea.
33. Lepage, R., J. Higgins, and G. Finch, Moisture
Uptake Testing for CLT Floor Panels in a Tall Wood
Building in Vancouver,in 15th Canadian Conference
on Building Science and Technology. 2017:
Vancouver, Canada.
34. Leyder, C., E. Chatzi, and A. Frangi, Structural
health monitor
ing of an innovative timber building
,
in International Conference on Performance-based
and Life-cycle Structural Engineering. 2015.
35. Mustapha, G., K. Khondoker, and J. Higgins,
MOISTURE PERFORMANCE AND VERTICAL
MOVEMENT MONITORING OF PRE-
FABRICATED CROSS LAMINATE TIMBER –
FEATURED CASE STUDY: UBC TALLWOOD
HOUSE, in 15th Canadian Conference on Building
Science and Technology. 2017: Vancouver, Canada.
36. Wang, J.Y., et al., DURABILITY OF MASS TIMBER
STRUCTURES: A REVIEW OF THE BIOLOGICAL
RISKS. Wood and Fiber Science, 2018. 50: p.
pp.110-127.
37. Wang, J., WETTING AND DRYING
PERFORMANCE OF WOOD-BASED ASSEMBLIES
RELATED TO ON-SITE MOISTURE
MANAGEMENT, in WCTE 2016 World Conference
on Timber Engineering, August 22-25. 2016: Vienna,
Austria.
38. Zelinka, S.L., et al., Moisture monitoring throughout
the construction and occupancy of mass timber
buildings, in 1 st International Conference on New
Horizons in Green Cicil Engineeirng (NHICE-01),
25-27 April. 2018: Victoria, BC, Canada.
39. CEN, EN 16351:2015, Timber structures - Cross
laminated timber - Requirements. 2015, European
Committee for Standardization: Brussels.
40. Brandner, R., Production and Technology of Cross
Laminated Timber (CLT): State-of-the-art Report, in
Focus Solid Timber Solutions - European Conference
on Cross Laminated Timber (CLT). 2013: Graz,
Austria.
41. Alsayegh, G., et al., Preliminary Characterization of
Physical Properties of Cross-Laminated-Timber
(CLT) Panels for Hygrothermal Modelling. ASTM
International, 2013. 2(1).
42. Matzinger, I. and I. Teibinger, Construction with
Cross-Laminated Timber in Multi-Storey Buildings
Focus on Building Physica- Guidelines. 2013,
Vienna, Austria: Holzforschung Austria. 145.
43. Thivierge, C., Building with CLT Panels Durability
Considerations, in Wood
Design & Building
- Winter
2011-12. 2012. p. 4.
44. Öberg, J. and E. Wiege, Fuktrisker på KL-trä som
utsätts för yttre klimat under produktion-fokus på
mögel och uppfuktning, in Byggteknik och Design.
2018, KTH, Kungliga Tekniska Högskolan:
Stockholm.
45. Dimstrand, D. and F. Jansson, KL-trä som
stommaterial, in
Fakulteten för hälsa, n
atur- och
teknikvetenskap. 2018, Karlstads Universitet:
Karlstad.
46. Gamboa, A.G., Water and Moisture in CLT. 2017,
Wood Science and Engineering: Luleå.
47. Gamboa, A.G., Effects of water and moisture in CLT
and how todry it. 2018, Wood Science and
Engineeering: Luleå.
48. SMHI. Open Data. 2019 [cited 2019 August];
Available from: https://www.smhi.se/data.
49. Thelandersson, S. and T. Isaksson, Mould resistance
design (MRD) model for evaluation of microbial
growth under varying climate conditions. . Building
& Environment 65, 2013.
50. SIS, SS-EN 13183-2, Moisture content of a piece of
sawn timber- Part 2: Estimation by electrical
resistance method
. 2003, Swedish Standards
Institute: Stockholm.
51. Hallenberg, N. and E. Gilert, Betingelser för
mögelpåväxt på trä - Klimatkammarstudier (SP
rapport 1988:57). 1988, Statens Provningsanstalt:
Borås.
E3S Web of Conferences 1
72, 10001 (2020)
NSB 2020
http://doi.org/10.1051/e3sconf/2020172 010 01
8
