Appendix A

REPORT ON ROOF LEAKS @

Frogmore Day Care Centre Potley Hill Road

Yateley GU46 6AG

17th April 2015

Contents 1. Brief ............................................................................................................................................. 3

2. Construction ................................................................................................................................ 3

3. Site Investigations ....................................................................................................................... 3

4. Summary of Findings .................................................................................................................. 3

5. Conclusions ................................................................................................................................. 4

6. Options for Repairs ..................................................................................................................... 4

7. Budget Costings .......................................................................................................................... 5

Appendix 1 - Redland Report dated 26th January 2015 ...................................................................... 6

Appendix 2 - Redland Report dated 17th March 2015 ......................................................................... 8

Appendix 3 - Technical data sheet on “thru vent” ............................................................................. 10

Appendix 4 - Photographs ................................................................................................................. 11

Appendix 5 - Brief .............................................................................................................................. 16

1. Brief As set out in John Elson’s email to Martin De Weid dated 15th August 2014 (copy attached). The building was constructed approximate 15 years ago but has suffered from roof leaks for a number of years. The scope of the inspection and report is limited to that required to identify the cause of the problem and recommend possible solutions together with estimated costs. Remedial repairs have been undertaken by others recently consisting of using a self adhesive flashband type material to seal over the through roof ventilators although this has not resolved the problems

2. Construction The roof structure consists of double timber principle rafters supported by steel lattice beam purlins with further timber purlins between the principle rafters supporting 150x50mm timber rafters @ 450mm approx. centres with BS747 1F bituminous sarking felt, timber battens and Redland Cambrian interlocking slates. A more detailed description of the roof coverings can be found in the Redland reports

3. Site Investigations Site investigations were carried out on two separate occasions the first one (26th January 2015) was of limited value due to restricted access caused by a wet / slippery roof surface The second one took place on the 17th March 2015 Both were attended by Redland after sales Manager Andy Stewart and operatives from Salnor Roofing Ltd. Slates were removed in a number of different locations across the roof. Two separate reports prepared by Redland record the findings (copies attached).

4. Summary of Findings Inside the building areas of brownish staining to plaster finishes indicating water penetration were evident along the length of the main room at the junction between sloping ceiling and walls but with no particular pattern which would suggest a specific location for the leaks except that the start of the staining appeared to coincide with the line of the through roof ventilators (this makes sense given the lack of underlay seals to the through roof vents, see attached product literature for details of underlay seals) Staining was also visible to the suspended ceiling tiles in the centre managers office

Externally the investigations revealed that the Redland Cambrian slates had not been installed in accordance with manufacturers recommendations. Numerous defects were noted:

1. A number of tile courses towards the apex of the roof did not have the recommended

minimum head lap i.e. 65 and 70mm instead of 75mm 2. The maximum rafter length has been exceeded i.e. 11.5m instead of 11.0m (this

increases the risk of sidelock flooding and therefore potential water ingress)

Building: Frogmore Daycare Centre, Potley Hill Road, Yateley GU46 6AG Client: Hart District Council Contact: John Elson Head of Technical & Environmental Services

Report by: Andrew Fellingham

3. A number of slates near the apex could be lifted along their leading edges indicating that the slates had not been twice nailed and clipped as required

4. Away from the valley area a number of slates had broken cover locks which could compromise the slates weather tightness

5. In the areas around the vent slates it was noted that adhesive had been used to secure the slate this also could compromise the slates weather tightness

6. Adhesive had also appeared to have been used to secure slates following previous investigation / repair works

7. Underlays seals had not been fitted to the slate vents 8. The sarking felt is very basic quality and has become brittle / fragile 9. Various rips and tears were noted to the sarking felt 10. The sarking felt in one area did not have sufficient head lap i.e. 75mm instead of

150mm 11. The over facia ventilation is insufficient 10mm instead of 25mm 12. Valley slate vents had not been installed 13. No high level ridge vents to the dual pitch sections of the ridge

5. Conclusions It was not possible to positively identify one specific defect which was responsible for the leaks however it seems likely that the numerous workmanship and other defects listed above coupled with the relatively low pitch @ 17 deg (the minimum recommended is 15 deg) and rafters which exceed the maximum permissible length allows heavy wind driven rain to be blown into the void under the slates.

The felt underlay which is of very basic quality has numerous holes and tears, lacks sufficient laps in some areas and crucially the waterproofing sleeves have not been fitted where roof vents penetrate the felt. This means that any water that does get under the slates will very quickly find its way into the building.

The investigations also revealed that the roof is inadequately ventilated which means that interstitial condensation make be a contributory factor.

6. Options for Repairs 1. To attempt to correct the numerous defects – This option is not recommended due to

the high number of defects, the difficulty in carrying out repairs without damaging the other slates and also the fact that the roof has defects which could not be corrected without stripping the entire roof ie the poor quality felt and excessive rafter length for Cambrian Slates

2. To remove the existing slates replace/upgrade the sarking felt and then re-fix the existing slates This option is not recommended since a high proportion of breakages could be expected and the new slates would not colour match the existing slates and also the excessive rafter length could not be resolved.

3. To remove the existing slates and replace them a different type of covering system for example lightweight metal tiles such as “icopal decra” or similar. This type of system will not impose any additional loads on the existing roof structure and should therefore be a relatively cost effective solution. Counter battening may be required to accommodate additional insulation to meet current building regulations. A budget cost for this option is included below.

4. Another possible solution would be to remove the existing slates and replace with a composite insulated profiled metal sheet (Kingspan or similar). A budget cost for this option is included below.

5. Note: Options 4 and 5 may need planning approval.

7. Budget Costings

Option 1 – Profiled Metal Sheet (Kingspan or similar)

Project Name: Frogmore Day Care Centre re re-roofing

Based on using a Kingspan type panel

Item COST

Construction Phase Management

£ 5,457.00

Priced Schedule

1 Preliminaries £ 6,640.00

2 Schedule of Works

£ 38,893.00

Sub Total

£ 50,990.00

Confirm OH&P from Core Section

7.5 %

3,824.25

Confirm Insurances from Core Section

0.8 %

438.51

Total £ 55,252.76

Notes on costings

1. Costs exclude VAT

2. Costs are based at 2nd quarter 2015

3. Costs exclude professional fees and building regs / planning fees

4. Costs are based on using the Hampshire and Surrey Local Areas Construction Framework to

procure the works

5. Costs are based on normal working hours

6. Costs exclude making good finishes / decorations internally

7. Costs exclude any possible asbestos removal

8. The price specifically excludes a temporary roof

9. Costs includes 5% contingency allowance

Option 2 – Lightweight Metal Tiles (decra or similar)

Estimated budget cost = £69,000.

Appendix 1 - Redland Report dated 26th January 2015

Appendix 2 - Redland Report dated 17th March 2015

Appendix 3 - Technical data sheet on “thru vent”

Appendix 4 - Photographs

Fig 5 Headlap

Fig 6 Headlap 2

Fig 7 General view of roof

Fig 8 Example of slate damage

Fig 9 Example of slate damage 2

Fig 10 Felt head lap

Appendix 5 - Brief