Construction site weather shielding and
condition control
The sole responsibility for the content of this publication lies with the authors. It does not necessarily
reflect the opinion of the European Union. Neither the EASME nor the European Commission are
responsible for any use that may be made of the information contained therein.
The control of conditions
on building site
• The control of conditions on site means the practises
which will ensure
•
•
•
•
Conditions of material installation
Hardening of concrete
Drying of structures
Producing healthy buildings
• Actions
• Schedule control
• Decent weather guard, heating and air ventilation
• Checking and regulating conditions, when needed
§
Gleaned from building
regulations:
• A building needs to be designed and constructed to
ensure it won’t cause hygiene or health risk to the
users or the neighbours when moisture condensates
to the parts of the building or inner surfaces of the
building. (Building regulations C2, 1.2 Essential
requirement)
• Those properties of a building must remain, with
typical maintenance, the whole economically
reasonable lifespan.
Exercise: Give examples of what the text means in
practise on site?
3
Correct site conditions are
important because:
•
•
•
•
in autumn the concrete won’t dry off.
in winter cold air trickles onto floor hence the concrete honing is delayed.
in spring dry air causes concrete cracking.
in summer wind and heat may cause concrete cracking.
Also too cold or too dry base may cause quality issues in concrete
•floors.
The number of rainy days and the
amount of rainwater
The number of rainy days
Month
(rainwater = 1.0 mm)
The amount of rain (mm)
Helsinki
Tampere
Jyväskylä
Oulu
I
10
10.5
11
8
I
47
II
8
7.5
7
7
II
III
8
8.5
9
7
IV
7
7.5
8
V
6
6.5
VI
8
VII
Jyväskylä
Oulu
45
43
30
36
33.5
31
23
III
38
37.5
37
24
6
IV
36
36.5
37
20
7
7
V
32
35
38
30
8.5
9
8
VI
49
54
59
45
8
9.5
11
9
VII
62
70.5
79
60
VIII
11
11
11
10
VIII
78
83
88
66
IX
10
10
10
9
IX
66
64.5
63
42
X
10
11
12
9
X
73
66.5
60
41
XI
12
12
12
10
XI
68
62.5
57
36
XII
11
11
11
9
XII
58
52.5
47
30
I-XII
109
118
99
I-XII
643
639
447
On average, it rains or snows
every third day.
Month
Helsinki Tampere
Tampere estmated
Source: Finnish meteorological
institute. Estimates counted
during the years1971-2000.
Conditions
Sources of structural moisture
Moisture sources, fully prefabricated building
8-9
l/Rm3
1-1.5
l/Rm3
Interior plaster
0.5
l/Rm3
Rainwater
1-5
l/Rm3
10-16
l/Rm3
Concrete
Smoothing compound
Total
Masonry walls
5-7
l/wall-m2
Rain 1 mm
Snow 1 cm
= 1 l/m2
= 1 l/m2
E.g. in Helsinki the amount of rainfall
in September onto 500 sqm concrete
floor is 500 m2 x 73 l/m2 = 36 500 l
Exercise: How much, in a typical rainy day in autumn, rains water falls on one
section of the apartment block? The section contains the apartments of a
stairwell (about 400m2). The amount of rainwater in a one day is 20 mm.
Answer: 400 m2 x 20 l/m2 = 8000 litres.
Pain points of moisture management
Lifting lugs,
fixing points,
balcony
brackets
Bendy slab brings
water to load
bearing walls
Excessive water tightness of base
floor
Difficult to
weather protect
the heat
insulations
Suspension rods
complicate the
use of tarpaulin
Connection of
vertical joints
Drying solutions
• Usually lots of rainwater runs off from
concrete floor to heat insulate.
• While installing, one must consider
that the water can release in a
controlled way from structures.
• Also when using the building, the
moisture can condense on the inner
surface of cladding. Ventilation routes
must always be in accordance with
plans.
The water drainage holes of the base
wall should not covered!
Concrete construction work
• Concrete structures tolerate
moisture well but they should dry
completely before coating works.
• The humidity of concrete
structures must be measured
before the coating works.
• Timber and precast concrete
units at same site require special
planning because the
evaporated water easily
condenses on the surface of
timber units.
Energy-efficient and moisture-safe
installations
The insulation and
ventilation
solutions must be
suitable for
manufacturing,
installing and
occupatian.
Details can be difficult to make, but
they need to be made carefully so
they will last decades.
Co-operation on site
• Co-operation with supervisor,
subcontractors and workers
helps create good construction
conditions.
• Must arrange and remember
• Protection methods
• Working order
• Scopes of contract
Supplier’s liabilities
Products must be delivered
• On site, dry and water sealed
• To intermediate depots and
properly stored.
Supervision of crucial structures
• In advance, it must be agreed
with supervisors how energy
efficient and healthy structures
will be built, controlled and
confirmed on the construction
site.
• It must be taken into account
that the work methods are
chosen according to design
concept.
Construction site weather shielding
The sole responsibility for the content of this publication lies with the authors. It does not necessarily
reflect the opinion of the European Union. Neither the EASME nor the European Commission are
responsible for any use that may be made of the information contained therein.
Construction site weather shielding
• Weather shields maintain a dry site. The costs
of shielding can be high, but better productivity,
occupational safety and quality means
significant economical savings.
•
When tented the work
continues despite of
raining.
Exercise:
Give examples of how weather guards can help decrease the costs.
Construction site weather shielding
• Air humidity must be monitored when working in weather shield.
• If RH rises constantly over 60%, must ventilation must be
increased.
A yearly tradition?
28.12.2014 Helsinki
(MTV3.fi)
25.3.2013
Vantaa
(YLE.FI)
8.3.2011 Oulu
(YLE.FI)
15.05.2010 Helsinki
(Eteläsuomen sanomat)
Water tight floor, ”finished first time”
Water tight floors and
sandwich panels create
dry working conditions
on floors below.
More about method: www.tut.fi/site
Facade could be closed– already at factory
• The windows can
be installed in the
elements already
at the factory 
Less heating and
covering on site.
Notice when installing :
• The position of elements can’t be checked from windows → Installation
line marks inside the element
• Windows protection in the factory
• It takes more time to create supply contracts
Roofs
• A roof can be ready built on
the ground and hoisted into
place.
• This saves both labour cost
and indirect cost.
• No need for scaffolding nor
safety railings…
• Roof insulation can be
installed immediately after
frame work and drying can
start quickly.
Principal of dry construction
Dry construction
1. The roof and the envelope the building
are waterproof or built inside the
weather guard.
2. Relative humidity is less than 70%.
3. (Temperature over 10 °C, heating on.)
Exercise: List construction works that
need to be made by following the rules of
dry construction.
Working plan of dry construction
• The weather guard planning is a
major part of the working plan.
• Construction plans, materials,
scaffolding, weather guard and
equipment for critical works are
good to get when the weather is
good.
• Always be prepared for rain. On
average, it rains or snows every
third day.
• Also construction sequence can
help or ruin the success of dry
construction
Exercise: List examples of mistakes in construction sequence.
Considerations for dry construction:
•
•
•
•
•
•
Different moisture resistance of different materials
Targets of site condition and the methods of control
Protection of site, structures and materials
Other requirements for site (previous work,…)
Heating and drying methods
Any special characteristic of the construction site
Building in winter
• Cover all structures from rain and snow.
• Close the envelope carefully – especially large
openings.
• Install temporary front doors in balcony-access
blocks.
• In tower blocks temporary doors or tarpaulins
may be used.
• Mechanically remove snow, do not melt it.
The sooner you close the envelope the more you benefit!
Good conditions promote productivity, increase performance,
reduce interruptions, increase work motivation, create positive image.
Protecting material
Shielding
• Rising damp
• Rain
Take care of
• Ventilation
• Leachate
Remember
• Transportation cover does not protect from rain sufficiently
• Avoid extended storage periods
Short-term storing outdoors
• Windows remain outside for a
short while, waiting to be
transported indoors. Always
prevent ground contact.
• Factory installed protection of these
windows is not sufficient.
• Notice water flow. Water must not
stay under or on top of material.
The good practices and principles required for the energy efficient building have been
included in the teaching material. The writers are not responsible for their suitability to
individual building projects as such. The individual building projects have to be made
according to the building design of the targets in question.
Thank you